Document:

EXHIBIT 10.2

                        MORTGAGE LOAN PURCHASE AGREEMENT
                        --------------------------------

            This Mortgage Loan Purchase Agreement (the "Agreement"), dated as of
December 21, 2007, is between Wells Fargo Asset Securities Corporation, a
Delaware corporation (the "Company"), and Wells Fargo Bank, N.A., a national
banking association (the "Seller" or "Wells Fargo Bank").

            The Company and the Seller hereby recite and agree as follows:

            1. Defined Terms. Terms used without definition herein shall have
the respective meanings assigned to them in the Pooling and Servicing Agreement,
dated as of December 21, 2007 (the "Pooling and Servicing Agreement"), among the
Company, Wells Fargo Bank, as master servicer (the "Master Servicer"), and HSBC
Bank USA, National Association, as trustee (the "Trustee"), relating to the
issuance of the Company's Mortgage Pass-Through Certificates, Series 2007-AR10
(the "Certificates") or, if not defined therein, in the underwriting agreement,
dated February 15, 2006, and terms agreement, dated November 29, 2007 (together,
the "Underwriting Agreement"), among the Company, Wells Fargo Bank and Merrill
Lynch, Pierce, Fenner & Smith Incorporated ("Merrill Lynch"), or in the purchase
agreement, dated May 10, 2004, and the purchaser terms agreement, dated November
29, 2007 (together, the "Purchase Agreement"), among the Company, Wells Fargo
Bank and Merrill Lynch.

            2. Assignment of Servicing Agreements. The Seller agrees to sell,
and the Company agrees to purchase, the mortgage loans (the "Mortgage Loans")
listed on the Mortgage Loan Schedule and all of the Seller's interest with
respect to the Mortgage Loans as the owner in, to and under each Servicing
Agreement.

            3. Purchase Price; Purchase and Sale. The purchase price (the
"Purchase Price") for the Mortgage Loans shall consist of $[______________]
payable by the Company to the Seller on the Closing Date in immediately
available funds.

            Upon payment of the Purchase Price, the Seller shall be deemed to
have transferred, assigned, set over and otherwise conveyed to the Company all
the right, title and interest of the Seller in and to the Mortgage Loans
including all interest and principal received or receivable by the Seller on or
with respect to the Mortgage Loans after the Cut-Off Date (and including
scheduled payments of principal and interest due after the Cut-Off Date but
received by the Seller on or before the Cut-Off Date and Principal Prepayments
received or applied on the Cut-Off Date, but not including payments of principal
and interest due on the Mortgage Loans on or before the Cut-Off Date), together
with all of the Seller's right, title and interest in and to the proceeds of any
related title, hazard, primary mortgage or other insurance policies, the
Seller's right to receive amounts, if any, payable on behalf of any Mortgagor
from the Subsidy Account relating to any Subsidy Loan, all of the Seller's
rights described in Section 2 above, and all other property and rights described
in the first paragraph of Section 2.01(a) of the Pooling and Servicing
Agreement. The Company hereby directs the Seller, and the Seller hereby agrees,
to deliver to the Trustee or Custodian on behalf of the Trustee, all documents,
instruments and agreements required to be delivered by the Company to the
Trustee under the Pooling and Servicing Agreement; including, without
limitation, the documents required to be delivered under Section 2.01(a) of the
Pooling and Servicing Agreement; and upon the occurrence of a Document Transfer
Event, the documents required to be delivered under Section 2.01(b). The Seller
further agrees to deliver such other documents, instruments and agreements as
the Company or the Trustee shall reasonably request.

            4. Representations and Warranties; Covenants. The Seller hereby
represents and warrants to the Company that (i) the Company's representations
and warranties to the Trustee pursuant to Section 2.03(b) of the Pooling and
Servicing Agreement are true and correct, as of the date thereof, and (ii)
Seller has not dealt with any broker, investment banker, agent or other person
(other than the Company and Merrill Lynch) who may be entitled to any commission
or compensation in connection with the sale of the Mortgage Loans. The Seller
hereby agrees to cure any breach of such representations and warranties in
accordance with the terms of the Pooling and Servicing Agreement.

            The Seller hereby agrees to continue to pay on behalf of the Company
and its successors and assignees, promptly as they become due, any lender-paid
primary mortgage insurance premiums ("LPMI Premiums") with respect to any
lender-paid primary mortgage insurance policy (an "LPMI Policy") on each
Mortgage Loan so insured as of the Cut-Off Date, until such Mortgage Loan has
been paid in full or otherwise liquidated; provided, however, that the foregoing
obligation of the Seller shall terminate with respect to all such Mortgage Loans
in the event that either (i) another entity acceptable to the insurers of such
LPMI Policies (the "LPMI Insurers") and the rating agencies rating the
Certificates undertakes to pay such LPMI Premiums, or (ii) the Seller pays
one-time premiums to such LPMI Insurers such that all outstanding LPMI Policies
will remain in force until the related Mortgage Loans have been paid in full or
otherwise liquidated, without the requirement of any further premium payments.

            5. Repurchase or Substitution. (a) The Seller hereby agrees to
repurchase any Mortgage Loan (i) for which any document is not delivered, as
provided in paragraph 3 above, (ii) which is found by the Trustee or the
Custodian to be defective in any material respect, as provided in the Pooling
and Servicing Agreement, or (iii) which is discovered at any time not to be in
conformance with the representations and warranties referred to in paragraph 4
above and which document relating thereto the Seller does not deliver or which
defect or breach the Seller does not cure (as provided in paragraph 4 above)
within 60 days after the date of notice thereof from the Trustee or the Company,
at a price equal to the Repurchase Price. In addition, the Seller hereby agrees
to reimburse the Company for any Reimbursement Amount. Alternatively, the Seller
hereby agrees, if so requested by the Company to substitute for any such
Mortgage Loan, a new mortgage loan having characteristics such that the
representations and warranties referred to in paragraph 4 above would not have
been incorrect (except for representations and warranties as to the correctness
of the Mortgage Loan Schedule) had such substitute mortgage loan originally been
a Mortgage Loan. The Seller further agrees that a substituted mortgage loan will
have (i) an unpaid principal balance no greater than the Scheduled Principal
Balance of the Mortgage Loan for which it is substituted (after giving effect to
the scheduled principal payment due in the month of substitution on the Mortgage
Loan for which such mortgage loan is substituted), (ii) a Net Mortgage Interest
Rate equal to and a Loan-to-Value Ratio no greater than that of the Mortgage
Loan for which it is substituted, (iii) the same Gross Margin and Index as that
of the Mortgage Loan for which it is substituted and (iv) the same frequency of
mortgage rate adjustment as that of the Mortgage Loan for which it is
substituted. The Seller shall remit to the Company, in cash, the difference
between the unpaid principal balance of the Mortgage Loan to be substituted and
the unpaid principal balance of the substitute mortgage loan.

            (b) In the event that the Seller has a right against the originator
or former owner (the "Prior Holder") of a Mortgage Loan which is in default or
as to which default is reasonably foreseeable for breach of a representation or
warranty regarding the characteristics of such Mortgage Loan made by the Prior
Holder, the Seller may request the Company to repurchase the Mortgage Loan from
the Trust Estate pursuant to Section 3.08 of the Pooling and Servicing Agreement
and the Seller agrees that at the time of the repurchase by the Company, the
Seller will repurchase the Mortgage Loan from the Company at a price equal to
the Repurchase Price.

            At the time of any such repurchase by the Seller, the Seller agrees
either to promptly (i) liquidate such Mortgage Loan, to the extent that the
Seller's rights in respect of the Prior Holder consist of a claim for indemnity
or (ii) transfer such Mortgage Loan to the Prior Holder at a price not less than
that paid by the Seller to the Company.

            6. Underwriting. The Seller hereby agrees to furnish any and all
information, documents, certificates, letters or opinions with respect to the
Mortgage Loans, reasonably requested by the Company in order to perform any of
its obligations or satisfy any of the conditions on its part to be performed or
satisfied pursuant to the Underwriting Agreement or the Purchase Agreement at or
prior to the Closing Date.

            7. Costs. The Company shall pay all expenses incidental to the
performance of its obligations under the Underwriting Agreement and the Purchase
Agreement, including without limitation (i) any recording fees or fees for title
policy endorsements and continuations, (ii) the expenses of preparing, printing
and reproducing the Prospectus, the Prospectus Supplement, the Underwriting
Agreement, the Private Placement Memorandum, the Purchase Agreement, the Pooling
and Servicing Agreement and the Certificates and (iii) the cost of delivering
the Certificates to the offices of Merrill Lynch insured to the satisfaction of
Merrill Lynch.

            8. Servicing. (a) The Seller hereby represents to the Company that
the Mortgage Loans are serviced by the Servicers. The Seller has delivered
copies of each Servicing Agreement to the Company, though omitting schedules of
mortgage loans which are serviced thereunder, but which are not being sold in
this transaction.

            (b) With respect to each Mortgage Loan, the Servicing Fee Rate and
the Master Servicing Fee Rate (which is in addition to the Servicing Fee Rate)
shall be as set forth on the Mortgage Loan Schedule.

            (c) On the Closing Date, the Seller shall assign to the Company its
interest with respect to the Mortgage Loans in, to and under each Servicing
Agreement.

            9. Notices. All demands, notices and communications hereunder shall
be in writing, shall be effective only upon receipt and shall, if sent to the
Company, be addressed to it at Wells Fargo Asset Securities Corporation, 5325
Spectrum Drive, Frederick, Maryland 21703, Attn: Vice President, Structured
Finance, or, if sent to the Seller, be addressed to it at Wells Fargo Bank,
N.A., 5325 Spectrum Drive, Frederick, Maryland, 21703, Attn: Vice President,
Structured Finance.

            10. Trustee Beneficiary. The representations, warranties and
agreements made by the Seller in this Agreement are made for the benefit of, and
may be enforced by, the Trustee and the holders of Certificates to the same
extent that the Trustee and the holders of Certificates, respectively, have
rights against the Company under the Pooling and Servicing Agreement in respect
of representations, warranties and agreements made by the Company therein.

            11. Recharacterization. The parties hereto intend the conveyance by
the Seller to the Company of all of its right, title and interest in and to the
Mortgage Loans pursuant to this Agreement to constitute a purchase and sale and
not a loan. Notwithstanding the foregoing, to the extent that such conveyance is
held not to constitute a sale under applicable law, it is intended that this
Agreement shall constitute a security agreement under applicable law and that
the Seller shall be deemed to have granted to the Company a first priority
security interest in all of the Seller's right, title and interest in and to the
Mortgage Loans.

            12. Miscellaneous. This Agreement shall be governed by and construed
in accordance with the laws of the State of New York. Neither this Agreement nor
any term hereof may be changed, waived, discharged or terminated except by a
writing signed by the party against whom enforcement of such change, waiver,
discharge or termination is sought. This Agreement may not be changed in any
manner which would have a material adverse effect on holders of Certificates
without the prior written consent of the Trustee. The Trustee shall be protected
in consenting to any such change to the same extent provided in Article VIII of
the Pooling and Servicing Agreement. This Agreement may be signed in any number
of counterparts, each of which shall be deemed an original, which taken together
shall constitute one and the same instrument. This Agreement shall bind and
inure to the benefit of and be enforceable by the Company and the Seller and
their respective successors and assigns.

<PAGE>

            IN WITNESS WHEREOF, the Company and the Seller have caused this
Agreement to be duly executed by their respective officers as of the day and
year first above written.

                                       WELLS FARGO ASSET SECURITIES
                                          CORPORATION

                                       By: /s/ Bradley A. Davis
                                           -------------------------------------
                                       Name:  Bradley A. Davis
                                       Title: Vice President

                                       WELLS FARGO BANK, N.A.

                                       By: /s/ Bradley A. Davis
                                          --------------------------------------
                                       Name:  Bradley A. Davis
                                       Title: Vice PresidentEXHIBIT 4.1

       ___________________________________________________________________

                    WELLS FARGO ASSET SECURITIES CORPORATION

                                   (Depositor)

                                       and

                             WELLS FARGO BANK, N.A.

                                (Master Servicer)

                                       and

                       HSBC BANK USA, NATIONAL ASSOCIATION

                                    (Trustee)

                         POOLING AND SERVICING AGREEMENT

                          Dated as of December 20, 2007

                                 $480,976,948.00

                       Mortgage Pass-Through Certificates
                                 Series 2007-17

        _________________________________________________________________

<PAGE>

                                TABLE OF CONTENTS

                                                                            Page

                                    ARTICLE I

                                   DEFINITIONS

Section 1.01   Definitions......................................................
Section 1.02   Acts of Holders..................................................
Section 1.03   Effect of Headings and Table of Contents.........................
Section 1.04   Benefits of Agreement............................................

                                    ARTICLE II

                           CONVEYANCE OF MORTGAGE LOANS;
                       ORIGINAL ISSUANCE OF THE CERTIFICATES

Section 2.01   Conveyance of Mortgage Loans.....................................
Section 2.02   Acceptance by Custodian..........................................
Section 2.03   Representations and Warranties of the Master
                Servicer and the Depositor......................................
Section 2.04   Execution and Delivery of Certificates...........................
Section 2.05   Designation of Certificates; Designation of
                Startup Day and Latest Possible Maturity Date...................

                                    ARTICLE III

                   ADMINISTRATION OF THE TRUST ESTATE; SERVICING
                               OF THE MORTGAGE LOANS

Section 3.01   Certificate Account..............................................
Section 3.02   Permitted Withdrawals from the Certificate
                Account.........................................................
Section 3.03   Advances by Master Servicer and Trustee..........................
Section 3.04   Custodian to Cooperate; Release of Owner
                Mortgage Loan Files and Retained Mortgage Loan
                Files...........................................................
Section 3.05   Annual Compliance Statements.....................................
Section 3.06   Title, Management and Disposition of Any REO
                Mortgage Loan...................................................
Section 3.07   Amendments to Servicing Agreements, Modification
                of Standard Provisions..........................................
Section 3.08   Oversight of Servicing...........................................
Section 3.09   Termination and Substitution of Servicing
                Agreements......................................................
Section 3.10   Application of Net Liquidation Proceeds..........................
Section 3.11   Assessment of Servicing Compliance; Registered
                Public Accounting Firm Attestation Reports......................
Section 3.12   Exchange Act Reports.............................................

                                    ARTICLE IV

                     DISTRIBUTIONS IN RESPECT OF CERTIFICATES;
                          PAYMENTS TO CERTIFICATEHOLDERS;
                              STATEMENTS AND REPORTS

Section 4.01   Distributions....................................................
Section 4.02   Allocation of Realized Losses....................................
Section 4.03   Paying Agent.....................................................
Section 4.04   Statements to Certificateholders; Reports to the
                Trustee and the Depositor.......................................
Section 4.05   Grantor Trust Administration.....................................
Section 4.06   Calculation of Amounts; Binding Effect of
                Interpretations and Actions of Master Servicer..................
Section 4.07   Reserved.........................................................
Section 4.08   Distributions on Exchangeable Certificates.......................

                                     ARTICLE V

                                 THE CERTIFICATES

Section 5.01   The Certificates.................................................
Section 5.02   Registration of Certificates.....................................
Section 5.03   Transfer of Exchangeable REMIC Certificates and
                Exchangeable Certificates.......................................
Section 5.04   Exchanges of Exchangeable REMIC Certificates and
                Exchangeable Certificates.......................................
Section 5.05   Mutilated, Destroyed, Lost or Stolen
                Certificates....................................................
Section 5.06   Persons Deemed Owners............................................
Section 5.07   Access to List of Certificateholders' Names and
                Addresses.......................................................
Section 5.08   Maintenance of Office or Agency..................................
Section 5.09   Definitive Certificates..........................................
Section 5.10   Notices to Clearing Agency.......................................

                                    ARTICLE VI

                       THE DEPOSITOR AND THE MASTER SERVICER

Section 6.01   Liability of the Depositor and the Master
                Servicer........................................................
Section 6.02   Merger or Consolidation of the Depositor or the
                Master Servicer.................................................
Section 6.03   Limitation on Liability of the Depositor, the
                Master Servicer and Others......................................
Section 6.04   Resignation of the Master Servicer...............................
Section 6.05   Compensation to the Master Servicer..............................
Section 6.06   Assignment or Delegation of Duties by Master
                Servicer........................................................
Section 6.07   Indemnification of Trustee and Depositor by
                Master Servicer.................................................
Section 6.08   Master Servicer Errors and Omissions Policy......................

                                    ARTICLE VII

                                      DEFAULT

Section 7.01   Events of Default................................................
Section 7.02   Other Remedies of Trustee........................................
Section 7.03   Directions by Certificateholders and Duties of
                Trustee During Event of Default.................................
Section 7.04   Action upon Certain Failures of the Master
                Servicer and upon Event of Default..............................
Section 7.05   Trustee to Act; Appointment of Successor.........................
Section 7.06   Notification to Certificateholders...............................

                                   ARTICLE VIII

                              CONCERNING THE TRUSTEE

Section 8.01   Duties of Trustee................................................
Section 8.02   Certain Matters Affecting the Trustee............................
Section 8.03   Trustee Not Required to Make Investigation.......................
Section 8.04   Trustee Not Liable for Certificates or Mortgage
                Loans...........................................................
Section 8.05   Trustee May Own Certificates.....................................
Section 8.06   The Master Servicer to Pay Fees and Expenses;
                Limitation on Liability.........................................
Section 8.07   Eligibility Requirements.........................................
Section 8.08   Resignation and Removal..........................................
Section 8.09   Successor........................................................
Section 8.10   Merger or Consolidation..........................................
Section 8.11   Authenticating Agent.............................................
Section 8.12   Separate Trustees and Co-Trustees................................
Section 8.13   Tax Matters; Compliance with REMIC Provisions....................
Section 8.14   Monthly Advances.................................................
Section 8.15   Indemnification of the Master Servicer and
                Depositor by the Trustee........................................
Section 8.16   Trustee Errors and Omissions Policy..............................

                                    ARTICLE IX

                                    TERMINATION

Section 9.01   Termination upon Purchase by the Depositor or
                Liquidation of All Mortgage Loans...............................
Section 9.02   Additional Termination Requirements..............................

                                     ARTICLE X

                             MISCELLANEOUS PROVISIONS

Section 10.01  Amendment........................................................
Section 10.02  Recordation of Agreement.........................................
Section 10.03  Limitation on Rights of Certificateholders.......................
Section 10.04  Governing Law; Jurisdiction......................................
Section 10.05  Notices..........................................................
Section 10.06  Severability of Provisions.......................................
Section 10.07  Special Notices to Rating Agencies...............................
Section 10.08  Covenant of Depositor............................................
Section 10.09  Recharacterization...............................................
Section 10.10  Regulation AB Compliance; Intent of Parties;
                Reasonableness..................................................

                                   ARTICLE XI

                             TERMS FOR CERTIFICATES

Section 11.01  Cut-Off Date.....................................................
Section 11.02  Cut-Off Date Aggregate Principal Balance.........................
Section 11.03  Original Class A Percentage......................................
Section 11.04  Reserved.........................................................
Section 11.05  Original Principal Balances or Maximum Initial
                Principal Balances of the Classes of Class A
                Certificates....................................................
Section 11.06  Original Aggregate Non-PO Principal Balance......................
Section 11.07  Original Class B Principal Balance...............................
Section 11.08  Original Principal Balances of the Classes of
                Class B Certificates............................................
Section 11.09  Original Class B-1 Fractional Interest...........................
Section 11.10  Original Class B-2 Fractional Interest...........................
Section 11.11  Original Class B-3 Fractional Interest...........................
Section 11.12  Original Class B-4 Fractional Interest...........................
Section 11.13  Original Class B-5 Fractional Interest...........................
Section 11.14  Original Class B-1 Percentage....................................
Section 11.15  Original Class B-2 Percentage....................................
Section 11.16  Original Class B-3 Percentage....................................
Section 11.17  Original Class B-4 Percentage....................................
Section 11.18  Original Class B-5 Percentage....................................
Section 11.19  Original Class B-6 Percentage....................................
Section 11.20  Closing Date.....................................................
Section 11.21  Right to Purchase................................................
Section 11.22  Single Certificate...............................................
Section 11.23  Servicing Fee Rate...............................................
Section 11.24  Master Servicing Fee Rate........................................
SCHEDULE I        -     Applicable Unscheduled Principal Receipt Period

<PAGE>

                                    EXHIBITS

EXHIBIT A-1       -     Form of Face of Class A-1 Certificate
EXHIBIT A-2       -     Form of Face of Class A-2 Certificate
EXHIBIT A-3       -     Form of Face of Class A-3 Certificate
EXHIBIT A-PO      -     Form of Face of Class A-PO Certificate
EXHIBIT A-R       -     Form of Face of Class A-R Certificate
EXHIBIT B-1       -     Form of Face of Class B-1 Certificate
EXHIBIT B-2       -     Form of Face of Class B-2 Certificate
EXHIBIT B-3       -     Form of Face of Class B-3 Certificate
EXHIBIT B-4       -     Form of Face of Class B-4 Certificate
EXHIBIT B-5       -     Form of Face of Class B-5 Certificate
EXHIBIT B-6       -     Form of Face of Class B-6 Certificate
EXHIBIT C         -     Form of Reverse of Series 2007-17 Certificates
EXHIBIT D         -     Reserved
EXHIBIT E         -     Custodial Agreement
EXHIBIT F         -     Addresses for Requesting Mortgage Loan Schedule
EXHIBIT G         -     Request for Release
EXHIBIT H         -     Affidavit Pursuant to Section 860E(e)(4) of the
                              Internal Revenue Code of 1986, as amended, and
                              for Non-ERISA Investors
EXHIBIT I         -     Letter from Transferor of Residual Certificate
EXHIBIT J         -     Transferee's Letter (Class [B-4] [B-5] [B-6]
                              Certificates)
EXHIBIT K         -     List of Recordation States
EXHIBIT L         -     Servicing Agreements
EXHIBIT M         -     Form of Special Servicing Agreement
EXHIBIT N         -     Form of Initial Certification of the Custodian
EXHIBIT O         -     Form of Final Certification of the Custodian
EXHIBIT P         -     Form of Sarbanes Oxley Certification
EXHIBIT Q         -     Reserved
EXHIBIT R         -     Servicing Criteria to be Addressed in Assessment of
                              Compliance
EXHIBIT S         -     Additional Form 10-D Disclosure
EXHIBIT T         -     Additional Form 10-K Disclosure
EXHIBIT U         -     Form 8-K Disclosure Information
EXHIBIT V         -     Additional Disclosure Notification
EXHIBIT W         -     Combination Groups
EXHIBIT X         -     Form of Request for Exchange of Exchangeable REMIC
                              Certificates or Exchangeable Certificates

<PAGE>

      This Pooling and Servicing Agreement, dated as of December 20,
2007, executed by WELLS FARGO ASSET SECURITIES CORPORATION, as Depositor,
WELLS FARGO BANK, N.A., as Master Servicer, and HSBC BANK USA, NATIONAL
ASSOCIATION, as Trustee.

                          W I T N E S S E T H  T H A T:

      In consideration of the mutual agreements herein contained, the
Depositor, the Master Servicer and the Trustee agree as follows:

                                    ARTICLE I

                                   DEFINITIONS

      Section 1.01 Definitions.

      Whenever used herein, the following words and phrases, unless the
context otherwise requires, shall have the meanings specified in this Article.

      1933 Act: The Securities Act of 1933, as amended.

      Accepted Master Servicing Practices: Accepted Master Servicing
Practices shall consist of the customary and usual master servicing practices
of prudent master servicing institutions which master service mortgage loans
of the same type as the Mortgage Loans in the jurisdictions in which the
related Mortgaged Properties are located, regardless of the date upon which
the related Mortgage Loans were originated.

      Additional Form 10-D Disclosure: As defined in Section 3.12(a).

      Additional Form 10-K Disclosure: As defined in Section 3.12(b).

      Additional Master Servicer: As defined in Section 6.06(b).

      Adjusted Pool Amount: With respect to any Distribution Date, the
Cut-Off Date Aggregate Principal Balance minus the sum of (i) all amounts in
respect of principal received in respect of the Mortgage Loans (including,
without limitation, amounts received as Monthly Payments, Periodic Advances,
Unscheduled Principal Receipts and Substitution Principal Amounts) and
distributed to Holders of the Certificates on such Distribution Date and all
prior Distribution Dates, (ii) the principal portion of all Liquidated Loan
Losses incurred on such Mortgage Loans for which the Liquidation Proceeds
were received from the Cut-Off Date through the end of the Applicable
Unscheduled Principal Receipt Period with respect to Full Unscheduled
Principal Receipts for such Distribution Date and (iii) the principal portion
of all Bankruptcy Losses (other than Debt Service Reductions) incurred on the
Mortgage Loans from the Cut-Off Date through the end of the period
corresponding to the Applicable Unscheduled Principal Receipt Period with
respect to Full Unscheduled Principal Receipts for such Distribution Date.

      Adjusted Pool Amount (Non-PO Portion): With respect to any Distribution
Date, the difference between the Adjusted Pool Amount and the Adjusted Pool
Amount (PO Portion).

      Adjusted Pool Amount (PO Portion): With respect to any Distribution
Date, the sum of the amounts, calculated as follows, with respect to all
Outstanding Mortgage Loans: the product of (i) the PO Fraction for each such
Mortgage Loan and (ii) the remainder of (A) the Cut-Off Date Principal
Balance of such Mortgage Loan minus (B) the sum of (x) all amounts in respect
of principal received in respect of such Mortgage Loan (including, without
limitation, amounts received as Monthly Payments, Periodic Advances,
Unscheduled Principal Receipts and Substitution Principal Amounts) and
distributed to Holders of the Certificates on such Distribution Date and all
prior Distribution Dates, (y) the principal portion of any Liquidated Loan
Losses incurred on such Mortgage Loans for which Liquidation Proceeds were
received from the Cut-Off Date through the end of the Applicable Unscheduled
Principal Receipt Period with respect to Full Unscheduled Principal Receipts
for such Distribution Date and (z) the principal portion of all Bankruptcy
Losses (other than Debt Service Reductions) incurred on the Mortgage Loans
from the Cut-Off Date through the end of the period corresponding to the
Applicable Unscheduled Principal Receipt Period with respect to Full
Unscheduled Principal Receipts for such Distribution Date.

      Adjusted Principal Balance: As to any Distribution Date and any Class
of Class B Certificates, the greater of (A) zero and (B) (i) the Principal
Balance of such Class with respect to such Distribution Date minus (ii) the
Adjustment Amount for such Distribution Date less the Principal Balances for
any Classes of Class B Certificates with higher numerical designations.

      Adjustment Amount: For any Distribution Date, the difference between
(A) the sum of the Class A Non-PO Principal Balance and the Class B Principal
Balance as of the related Determination Date and (B) the sum of (i) the sum
of the Class A Non-PO Principal Balance and the Class B Principal Balance as
of the Determination Date succeeding such Distribution Date and (ii) the
aggregate amount that would have been distributed to all Classes of Class A
Non-PO Certificates and the Class B Certificates as principal in accordance
with Section 4.01(a) for such Distribution Date without regard to the
provisos in the definitions of Class B-1 Optimal Principal Amount, Class B-2
Optimal Principal Amount, Class B-3 Optimal Principal Amount, Class B-4
Optimal Principal Amount, Class B-5 Optimal Principal Amount and Class B-6
Optimal Principal Amount.

      Aggregate Class A Unpaid Interest Shortfall: As to any Distribution
Date, an amount equal to the sum of the Class A Unpaid Interest Shortfalls
for all the Classes of Class A Certificates.

      Aggregate Non-PO Principal Balance: As of any Determination Date, the
sum of the Class A Non-PO Principal Balance and the Class B Principal Balance
as of such date.

      Aggregate Principal Balance: As of any Determination Date, the sum of
the Class A Principal Balance and the Class B Principal Balance as of such
date.

      Agreement: This Pooling and Servicing Agreement and all amendments and
supplements hereto.

      Applicable Unscheduled Principal Receipt Period: With respect to the
Mortgage Loans serviced by each Servicer and each of the Full Unscheduled
Principal Receipts and Partial Unscheduled Principal Receipts, the
Unscheduled Principal Receipt Period specified on Schedule I hereto, as
amended by the Master Servicer pursuant to Section 10.01(b) hereof.

      Authenticating Agent: Any authenticating agent appointed by the Trustee
pursuant to Section 8.11. Initially, the Master Servicer shall be the
Authenticating Agent for the Certificates.

      Available Master Servicer Compensation: With respect to any
Distribution Date, the sum of (a) the Master Servicing Fee for such
Distribution Date, (b) interest earned through the business day preceding the
applicable Distribution Date on any Prepayments in Full remitted to the
Master Servicer and (c) the aggregate amount of Month End Interest remitted
by the Servicers to the Master Servicer pursuant to the related Servicing
Agreements.

      Balloon Loan: A Mortgage Loan that provides for a Balloon Payment.

      Balloon Payment: A payment of the unamortized principal balance of a
Mortgage Loan in a single payment at the maturity of such Mortgage Loan that
is greater than the preceding Monthly Payment.

      Bankruptcy Code: The Bankruptcy Code of 1978, as amended.

      Bankruptcy Loss: With respect to any Mortgage Loan, a Deficient
Valuation or Debt Service Reduction; provided, however, that a Bankruptcy
Loss shall not be deemed a Bankruptcy Loss hereunder so long as the
applicable Servicer has notified the Master Servicer and the Trustee in
writing that such Servicer is diligently pursuing any remedies that may exist
in connection with the representations and warranties made regarding the
related Mortgage Loan and either (A) the related Mortgage Loan is not in
default with regard to payments due thereunder or (B) delinquent payments of
principal and interest under the related Mortgage Loan and any premiums on
any applicable primary hazard insurance policy and any related escrow
payments in respect of such Mortgage Loan are being advanced on a current
basis by such Servicer without giving effect to any Debt Service Reduction.

      Beneficial Owner: With respect to a Book-Entry Certificate, the Person
who is the beneficial owner of such Book-Entry Certificate, as reflected on
the books of the Clearing Agency, or on the books of a Person maintaining an
account with such Clearing Agency (directly or as an indirect participant, in
accordance with the rules of such Clearing Agency), as the case may be.

      Book-Entry Certificate: Any one of the Class A Certificates (other than
the Class A-R Certificate) and Class B Certificates, beneficial ownership and
transfers of which shall be evidenced by, and made through, book entries by
the Clearing Agency as described in Section 5.01(b).

      Business Day: Any day other than (i) a Saturday or a Sunday, or (ii) a
legal holiday in the City of New York, State of Iowa, State of Maryland or
State of Minnesota or (iii) a day on which banking institutions in the City
of New York, or the State of Iowa, State of Maryland or State of Minnesota
are authorized or obligated by law or executive order to be closed.

      Capitalized Advance Amount: As defined in the related Servicing
Agreement.

      Certificate: Any one of the Class A Certificates or Class B
Certificates.

      Certificate Account: The separate trust account established and
maintained by the Master Servicer pursuant to Section 3.01 which shall be
entitled "Certificate Account, Wells Fargo Bank, N.A., as Master Servicer on
behalf of the Trustee, in trust for the Holders of the Certificates of the
Wells Fargo Mortgage Backed Securities 2007-17 Trust." The Certificate
Account shall be an Eligible Account.

      Certificate Custodian: Initially, Wells Fargo Bank; thereafter any
other Certificate Custodian acceptable to DTC and selected by the Trustee.

      Certificate Register and Certificate Registrar: Respectively, the
register maintained pursuant to and the registrar provided for in Section
5.02. Initially the Certificate Registrar shall be the Master Servicer.

      Certificateholder or Holder: The Person in whose name a Certificate is
registered in the Certificate Register, except that, solely for the purposes
of the taking of any action under Articles VII or VIII, any Certificate
registered in the name of the Master Servicer, a Servicer or any affiliate
thereof shall be deemed not to be outstanding and the Voting Interest
evidenced thereby shall not be taken into account in determining whether the
requisite percentage of Certificates necessary to effect any such action has
been obtained.

      Class: All certificates whose form is identical except for variations
in the Percentage Interest evidenced thereby.

      Class A Certificate: Any of the Class A-1 Certificates, Class A-2
Certificates, Class A-3 Certificates, Class A-PO Certificates and Class A-R
Certificate.

      Class A Certificateholder: The registered holder of a Class A
Certificate.

      Class A Distribution Amount: As to any Distribution Date and any Class
of Class A Certificates (other than the Class A-PO Certificates and the
Exchangeable Certificates), the amount distributable to such Class of Class A
Certificates pursuant to Paragraphs first, second and third clause (1) of
Section 4.01(a). As to any Distribution Date and the Class A-PO Certificates,
the amount distributable to the Class A-PO Certificates pursuant to
Paragraphs third clause (2) and fourth of Section 4.01(a) on such
Distribution Date. As to any Distribution Date and a Class of Exchangeable
Certificates, the amount distributable to such Class of Exchangeable
Certificates pursuant to Section 4.01(g) on such Distribution Date.

      Class A Interest Accrual Amount: As to any Distribution Date, the sum
of the Interest Accrual Amounts for the Class A Certificates with respect to
such Distribution Date.

      Class A Interest Percentage: As to any Distribution Date and any Class
of Class A Certificates, the percentage calculated by dividing the Interest
Accrual Amount of such Class (determined without regard to clause (ii) of the
definition thereof) by the Class A Interest Accrual Amount (determined
without regard to clause (ii) of the definition of each Interest Accrual
Amount).

      Class A Interest Shortfall Amount: As to any Distribution Date and any
Class of Class A Certificates, any amount by which the Interest Accrual
Amount of such Class with respect to such Distribution Date exceeds the
amount distributed in respect of such Class on such Distribution Date
pursuant to Paragraph first of Section 4.01(a).

      Class A Interest Shortfall Percentage: As to any Distribution Date and
any Class of Class A Certificates, the percentage calculated by dividing the
Class A Unpaid Interest Shortfall for such Class by the Aggregate Class A
Unpaid Interest Shortfall, in each case determined as of the day preceding
the applicable Distribution Date.

      Class A Loss Denominator: As to any Determination Date, an amount equal
to the Class A Non-PO Principal Balance.

      Class A Loss Percentage: As to any Determination Date and any Class of
Class A Certificates (other than the Class A-PO Certificates), the percentage
calculated by dividing the Principal Balance of such Class by the Class A
Loss Denominator (determined without regard to any such Principal Balance of
any Class of Class A Certificates not then outstanding), in each case
determined as of the preceding Determination Date.

      Class A Non-PO Certificate: Any of the Class A Certificates (other than
the Class A-PO Certificates and the Exchangeable Certificates).

      Class A Non-PO Optimal Principal Amount: As to any Distribution Date,
an amount equal to the sum of (I) the sum, as to each Mortgage Loan that is
an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Mortgage Loan, and (y) the sum of:

      (i) the Class A Percentage of the principal portion of the Monthly
   Payment due on the Due Date occurring in the month of such Distribution
   Date on such Mortgage Loan;

      (ii) the Class A Prepayment Percentage of all Unscheduled Principal
   Receipts (other than Recoveries) that were received by a Servicer with
   respect to such Mortgage Loan during the Applicable Unscheduled Principal
   Receipt Period relating to such Distribution Date for each applicable type
   of Unscheduled Principal Receipt;

      (iii) the Class A Prepayment Percentage of the Scheduled Principal
   Balance of such Mortgage Loan which, during the one month period ending on
   the day preceding the Determination Date for such Distribution Date, was
   repurchased by the Depositor pursuant to Section 2.02, 2.03 or 3.08; and

      (iv) the Class A Percentage of the Substitution Principal Amount with
   respect to each Mortgage Loan for which a Mortgage Loan was substituted
   during the one month period ending on the day preceding the Determination
   Date for such Distribution Date, less the amount allocable to the
   principal portion of any unreimbursed Periodic Advances previously made by
   the applicable Servicer, the Master Servicer or the Trustee in respect of
   such Mortgage Loan for which a Mortgage Loan was substituted; and

   (II) the Class A Prepayment Percentage of the Non-PO Recovery for such
   Distribution Date.

      Class A Non-PO Principal Balance: As of any date, an amount equal to
the Class A Principal Balance less the Principal Balance of the Class A-PO
Certificates.

      Class A Non-PO Principal Distribution Amount: As to any Distribution
Date, the aggregate amount distributed in respect of the Classes of Class A
Non-PO Certificates pursuant to Paragraph third clause (1) of Section 4.01(a).

      Class A Pass-Through Rate: As to the Class A Certificates (other than
the Class A-PO Certificates), 6.000% per annum. The Class A-PO Certificates
are not entitled to interest and have no Class A Pass-Through Rate.

      Class A Percentage: As to any Distribution Date occurring on or prior
to the Subordination Depletion Date, the lesser of (i) 100% and (ii) the
percentage obtained by dividing the Class A Non-PO Principal Balance
(determined as of the Determination Date preceding such Distribution Date) by
the Pool Balance (Non-PO Portion). As to any Distribution Date occurring
subsequent to the Subordination Depletion Date, 100% or such lesser
percentage which will cause the Class A Non-PO Principal Balance to decline
to zero following the distribution made on such Distribution Date.

      Class A Prepayment Percentage: As to any Distribution Date to and
including the Distribution Date in December 2012, 100%. As to any
Distribution Date subsequent to December 2012 to and including the
Distribution Date in December 2013, the Class A Percentage as of such
Distribution Date plus 70% of the Subordinated Percentage as of such
Distribution Date. As to any Distribution Date subsequent to December 2013 to
and including the Distribution Date in December 2014, the Class A Percentage
as of such Distribution Date plus 60% of the Subordinated Percentage as of
such Distribution Date. As to any Distribution Date subsequent to December
2014 to and including the Distribution Date in December 2015, the Class A
Percentage as of such Distribution Date plus 40% of the Subordinated
Percentage as of such Distribution Date. As to any Distribution Date
subsequent to December 2015 to and including the Distribution Date in
December 2016, the Class A Percentage as of such Distribution Date plus 20%
of the Subordinated Percentage as of such Distribution Date. As to any
Distribution Date subsequent to December 2016, the Class A Percentage as of
such Distribution Date. The foregoing is subject to the following: (i) if the
aggregate distribution to Holders of Class A Certificates on any Distribution
Date of the Class A Prepayment Percentage provided above of Unscheduled
Principal Receipts distributable on such Distribution Date would reduce the
Class A Non-PO Principal Balance below zero, the Class A Prepayment
Percentage for such Distribution Date shall be the percentage necessary to
bring the Class A Non-PO Principal Balance to zero and thereafter the Class A
Prepayment Percentage shall be zero and (ii) if the Class A Percentage as of
any Distribution Date is greater than the Original Class A Percentage, the
Class A Prepayment Percentage for such Distribution Date shall be 100%.
Notwithstanding the foregoing, with respect to any Distribution Date on which
the following criteria are not met, the reduction of the Class A Prepayment
Percentage described in the second through sixth sentences of this definition
of Class A Prepayment Percentage shall not be applicable with respect to such
Distribution Date. In such event, the Class A Prepayment Percentage for such
Distribution Date will be determined in accordance with the applicable
provision, as set forth in the first through fifth sentences above, which was
actually used to determine the Class A Prepayment Percentage for the
Distribution Date occurring in the December preceding such Distribution Date
(it being understood that for the purposes of the determination of the Class
A Prepayment Percentage for the current Distribution Date, the current Class
A Percentage and Subordinated Percentage shall be utilized).

      No reduction in the Class A Prepayment Percentage referred to in the
second through sixth sentences hereof shall be applicable with respect to any
Distribution Date if (a) the average outstanding principal balance on such
Distribution Date and for the preceding five Distribution Dates on the
Mortgage Loans that were delinquent 60 days or more (including for this
purpose any Mortgage Loans in foreclosure, any REO Mortgage Loans and any
Mortgage Loans that were the subject of a Servicer Modification within twelve
months prior to such Distribution Date) were greater than or equal to 50% of
the Class B Principal Balance or (b) cumulative Realized Losses on the
Mortgage Loans exceed (1) 30% of the Original Class B Principal Balance if
such Distribution Date occurs between and including January 2013 and December
2013, (2) 35% of the Original Class B Principal Balance if such Distribution
Date occurs between and including January 2014 and December 2014, (3) 40% of
the Original Class B Principal Balance if such Distribution Date occurs
between and including January 2015 and December 2015, (4) 45% of the Original
Class B Principal Balance if such Distribution Date occurs between and
including January 2016 and December 2016, and (5) 50% of the Original Class B
Principal Balance if such Distribution Date occurs during or after January
2017. With respect to any Distribution Date on which the Class A Prepayment
Percentage is reduced below the Class A Prepayment Percentage for the prior
Distribution Date, the Master Servicer shall certify to the Trustee, based
upon information provided by each Servicer as to the Mortgage Loans serviced
by it that the criteria set forth in the preceding sentence are met.

      Class A Principal Balance: As of any date, an amount equal to the sum
of the Principal Balances for the Class A Certificates.

      Class A Unpaid Interest Shortfall: As to any Distribution Date and any
Class of Class A Certificates, the amount, if any, by which the aggregate of
the Class A Interest Shortfall Amounts for such Class for prior Distribution
Dates is in excess of the amounts distributed in respect of such Class on
prior Distribution Dates pursuant to Paragraph second of Section 4.01(a).

      Class A-1 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially
the form set forth in Exhibit A-1 and Exhibit C hereto.

      Class A-1 Certificateholder: The registered holder of a Class A-1
Certificate.

      Class A-2 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially
the form set forth in Exhibit A-2 and Exhibit C hereto.

      Class A-2 Certificateholder: The registered holder of a Class A-2
Certificate.

      Class A-2 Loss Amount: With respect to any Determination Date after the
Subordination Depletion Date, the amount, if any, by which the Principal
Balance of the Class A-2 Certificates would be reduced as a result of the
application of the third sentence of the definition of Principal Balance.

      Class A-3 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially
the form set forth in Exhibit A-3 and Exhibit C hereto.

      Class A-3 Certificateholder: The registered holder of a Class A-3
Certificate.

      Class A-3 Loss Allocation Amount: With respect to any Determination
Date after the Subordination Depletion Date the lesser of (a) the Principal
Balance of the Class A-3 Certificates with respect to such Determination Date
prior to any reduction for the Class A-3 Loss Allocation Amount and (b) the
Class A-2 Loss Amount.

      Class A-PO Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially
the form set forth in Exhibit A-PO and Exhibit C hereto.

      Class A-PO Certificateholder: The registered holder of a Class A-PO
Certificate.

      Class A-PO Deferred Amount: For any Distribution Date prior to the
Subordination Depletion Date, the difference between (A) the sum of (x) the
amount by which the sum of the Class A-PO Optimal Principal Amounts for all
prior Distribution Dates exceeded the amounts distributed on the Class A-PO
Certificates on such prior Distribution Dates pursuant to Paragraph third
clause (2) of Section 4.01(a) and (y) the sum of the product for each
Discount Mortgage Loan which became a Liquidated Loan at any time on or prior
to the last day of the Applicable Unscheduled Principal Receipt Period for
Full Unscheduled Principal Receipts for the current Distribution Date of (a)
the PO Fraction for such Discount Mortgage Loan and (b) an amount equal to
the principal portion of Realized Losses (other than Bankruptcy Losses due to
Debt Service Reductions) incurred with respect to such Discount Mortgage Loan
and (B) the sum of (x) the sum of the Class A-PO Recoveries for such
Distribution Date and prior Distribution Dates and (y) amounts distributed on
the Class A-PO Certificates on prior Distribution Dates pursuant to Paragraph
fourth of Section 4.01(a). On and after the Subordination Depletion Date, the
Class A-PO Deferred Amount will be zero. No interest will accrue on any Class
A-PO Deferred Amount.

      Class A-PO Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Mortgage Loan that is an
Outstanding Mortgage Loan, of the product of (x) the PO Fraction with respect
to such Mortgage Loan and (y) the sum of:

      (i) the principal portion of the Monthly Payment due on the Due Date
   occurring in the month of such Distribution Date on such Mortgage Loan;

      (ii) all Unscheduled Principal Receipts (other than Recoveries) that were
   received by a Servicer with respect to such Mortgage Loan during the
   Applicable Unscheduled Principal Receipt Period relating to such Distribution
   Date for each applicable type of Unscheduled Principal Receipt;

      (iii) the Scheduled Principal Balance of each Mortgage Loan which, during
   the one month period ending on the day preceding the Determination Date for
   such Distribution Date, was repurchased by the Depositor pursuant to Section
   2.02, 2.03 or 3.08; and

      (iv) the Substitution Principal Amount with respect to each Mortgage Loan
   for which a Mortgage Loan was substituted during the one month period ending
   on the day preceding the Determination Date for such Distribution Date, less
   the amount allocable to the principal portion of any unreimbursed Periodic
   Advances previously made by the applicable Servicer, the Master Servicer or
   the Trustee in respect of such Mortgage Loan for which a Mortgage Loan was
   substituted; and

   (II) the Class A-PO Recovery for such Distribution Date.

      Class A-PO Recovery: As to any Distribution Date prior to the
Subordination Depletion Date, the lesser of (a) the Class A-PO Deferred
Amount for such Distribution Date (calculated without regard to the
Class A-PO Recovery for such Distribution Date) and (b) an amount equal to
the sum as to each Mortgage Loan as to which there has been a Recovery during
the Applicable Unscheduled Principal Receipt Period, of the product of
(x) the PO Fraction with respect to such Mortgage Loan and (y) the amount of
the Recovery with respect to such Mortgage Loan. As to any Distribution Date
on or after the Subordination Depletion Date, the amount determined in
accordance with clause (b) above.

      Class A-R Certificate: The Certificate executed by the Paying Agent and
countersigned by the Authenticating Agent in substantially the form set forth
in Exhibit A-R and Exhibit C hereto.

      Class A-R Certificateholder: The registered holder of the Class A-R
Certificate.

      Class B Certificate: Any of the Class B-1 Certificates, Class B-2
Certificates, Class B-3 Certificates, Class B-4 Certificates, Class B-5
Certificates or Class B-6 Certificates.

      Class B Certificateholder: The registered holder of a Class B
Certificate.

      Class B Distribution Amount: Any of the Class B-1, Class B-2, Class
B-3, Class B-4, Class B-5 and Class B-6 Distribution Amounts.

      Class B Interest Accrual Amount: With respect to any Distribution Date,
the sum of the Interest Accrual Amounts for the Classes of Class B
Certificates with respect to such Distribution Date.

      Class B Interest Percentage: With respect to any Distribution Date and
any Class of Class B Certificates, the percentage calculated by dividing the
Interest Accrual Amount of such Class (determined without regard to clause
(ii) of the definition thereof) by the Class B Interest Accrual Amount
(determined without regard to clause (ii) of the definition of each Interest
Accrual Amount).

      Class B Interest Shortfall Amount: Any of the Class B-1 Interest
Shortfall Amount, Class B-2 Interest Shortfall Amount, Class B-3 Interest
Shortfall Amount, Class B-4 Interest Shortfall Amount, Class B-5 Interest
Shortfall Amount or Class B-6 Interest Shortfall Amount.

      Class B Loss Percentage: With respect to any Determination Date and any
Class of Class B Certificates then outstanding, the percentage calculated by
dividing the Principal Balance of such Class by the Class B Principal Balance
(determined without regard to any Principal Balance of any Class of Class B
Certificates not then outstanding), in each case determined as of the
preceding Determination Date.

      Class B Optimal Principal Amount: Any of the Class B-1, Class B-2,
Class B-3, Class B-4, Class B-5 or Class B-6 Optimal Principal Amounts.

      Class B Pass-Through Rate: As to any Distribution Date, a per annum
rate equal to 6.000%.

      Class B Percentage: Any one of the Class B-1 Percentage, Class B-2
Percentage, Class B-3 Percentage, Class B-4 Percentage, Class B-5 Percentage
or Class B-6 Percentage.

      Class B Prepayment Percentage: Any of the Class B-1 Prepayment
Percentage, Class B-2 Prepayment Percentage, Class B-3 Prepayment Percentage,
Class B-4 Prepayment Percentage, Class B-5 Prepayment Percentage or Class B-6
Prepayment Percentage.

      Class B Principal Balance: As of any date, an amount equal to the sum
of the Class B-1 Principal Balance, Class B-2 Principal Balance, Class B-3
Principal Balance, Class B-4 Principal Balance, Class B-5 Principal Balance
and Class B-6 Principal Balance.

      Class B Unpaid Interest Shortfall: Any of the Class B-1 Unpaid Interest
Shortfall, Class B-2 Unpaid Interest Shortfall, Class B-3 Unpaid Interest
Shortfall, Class B-4 Unpaid Interest Shortfall, Class B-5 Unpaid Interest
Shortfall or Class B-6 Unpaid Interest Shortfall.

      Class B-1 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially
the form set forth in Exhibit B-1 and Exhibit C hereto.

      Class B-1 Certificateholder: The registered holder of a Class B-1
Certificate.

      Class B-1 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class B-1 Certificates pursuant to
Paragraphs fifth, sixth and seventh of Section 4.01(a).

      Class B-1 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class B-1 Certificates
with respect to such Distribution Date exceeds the amount distributed in
respect of the Class B-1 Certificates on such Distribution Date pursuant to
Paragraph fifth of Section 4.01(a).

      Class B-1 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan,
of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan
and (y) the sum of:

      (i) the Class B-1 Percentage of the principal portion of the Monthly
   Payment due on the Due Date occurring in the month of such Distribution
   Date on such Mortgage Loan;

      (ii) the Class B-1 Prepayment Percentage of all Unscheduled Principal
   Receipts (other than Recoveries) that were received by a Servicer with
   respect to such Mortgage Loan during the Applicable Unscheduled Principal
   Receipt Period relating to such Distribution Date for each applicable type
   of Unscheduled Principal Receipt;

      (iii) the Class B-1 Prepayment Percentage of the Scheduled Principal
   Balance of such Mortgage Loan which, during the one month period ending on
   the day preceding the Determination Date for such Distribution Date, was
   repurchased by the Depositor pursuant to Section 2.02, 2.03 or 3.08; and

      (iv) the Class B-1 Percentage of the Substitution Principal Amount with
   respect to each Mortgage Loan for which a Mortgage Loan was substituted
   during the one month period ending on the day preceding the Determination
   Date for such Distribution Date, less the amount allocable to the
   principal portion of any unreimbursed Periodic Advances previously made by
   the applicable Servicer, the Master Servicer or the Trustee in respect of
   such Mortgage Loan for which a Mortgage Loan was substituted; and

   (II) the Class B-1 Prepayment Percentage of the Non-PO Recovery for such
   Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class B-1 Optimal Principal Amount
will equal the lesser of (A) the Class B-1 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class B-1 Certificates.

      Class B-1 Percentage: As to any Distribution Date, the percentage
calculated by multiplying the Subordinated Percentage by either (i) if any
Class B Certificates (other than the Class B-1 Certificates) are eligible to
receive principal distributions for such Distribution Date in accordance with
Section 4.01(d), a fraction, the numerator of which is the Class B-1
Principal Balance (determined as of the Determination Date preceding such
Distribution Date) and the denominator of which is the sum of the Principal
Balances of the Classes of Class B Certificates eligible to receive principal
distributions for such Distribution Date in accordance with the provisions of
Section 4.01(d) or (ii) except as set forth in Section 4.01(d)(ii), in the
event that the Class B Certificates (other than the Class B-1 Certificates)
are not eligible to receive distributions of principal in accordance with
Section 4.01(d)(i), one.

      Class B-1 Prepayment Percentage: As to any Distribution Date, the
percentage calculated by multiplying the Subordinated Prepayment Percentage
by either (i) if any Class B Certificates (other than the Class B-1
Certificates) are eligible to receive principal distributions for such
Distribution Date in accordance with Section 4.01(d), a fraction, the
numerator of which is the Class B-1 Principal Balance (determined as of the
Determination Date preceding such Distribution Date) and the denominator of
which is the sum of the Principal Balances of the Classes of Class B
Certificates eligible to receive principal distributions for such
Distribution Date in accordance with the provisions of Section 4.01(d) or
(ii) except as set forth in Section 4.01(d)(ii), in the event that the Class
B Certificates (other than the Class B-1 Certificates) are not eligible to
receive distributions of principal in accordance with Section 4.01(d)(i), one.

      Class B-1 Principal Balance: As to the first Determination Date, the
Original Class B-1 Principal Balance. As of any subsequent Determination
Date, the Original Class B-1 Principal Balance less the sum of all amounts
previously distributed in respect of the Class B-1 Certificates on prior
Distribution Dates (A) pursuant to Paragraph seventh of Section 4.01(a)
(including any principal otherwise payable to the Class B-1 Certificates used
to pay any Class A-PO Deferred Amounts) and (B) as a result of a Principal
Adjustment; provided, however, if the Class B-1 Certificates are the most
subordinate Certificates outstanding, the Class B-1 Principal Balance will
equal the difference, if any, between the Adjusted Pool Amount (Non-PO
Portion) as of the preceding Distribution Date less the Class A Non-PO
Principal Balance as of such Determination Date.

      Class B-1 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class B-1 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed
in respect of the Class B-1 Certificates on prior Distribution Dates pursuant
to Paragraph sixth of Section 4.01(a).

      Class B-2 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially
the form set forth in Exhibit B-2 and Exhibit C hereto.

      Class B-2 Certificateholder: The registered holder of a Class B-2
Certificate.

      Class B-2 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class B-2 Certificates pursuant to
Paragraphs eighth, ninth and tenth of Section 4.01(a).

      Class B-2 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class B-2 Certificates
with respect to such Distribution Date exceeds the amount distributed in
respect of the Class B-2 Certificates on such Distribution Date pursuant to
Paragraph eighth of Section 4.01(a).

      Class B-2 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan,
of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan
and (y) the sum of:

      (i) the Class B-2 Percentage of the principal portion of the Monthly
   Payment due on the Due Date occurring in the month of such Distribution
   Date on such Mortgage Loan;

      (ii) the Class B-2 Prepayment Percentage of all Unscheduled Principal
   Receipts (other than Recoveries) that were received by a Servicer with
   respect to such Mortgage Loan during the Applicable Unscheduled Principal
   Receipt Period relating to such Distribution Date for each applicable type
   of Unscheduled Principal Receipt;

      (iii) the Class B-2 Prepayment Percentage of the Scheduled Principal
   Balance of such Mortgage Loan which, during the one month period ending on
   the day preceding the Determination Date for such Distribution Date, was
   repurchased by the Depositor pursuant to Section 2.02, 2.03 or 3.08; and

      (iv) the Class B-2 Percentage of the Substitution Principal Amount with
   respect to each Mortgage Loan for which a Mortgage Loan was substituted
   during the one month period ending on the day preceding the Determination
   Date for such Distribution Date, less the amount allocable to the
   principal portion of any unreimbursed Periodic Advances previously made by
   the applicable Servicer, the Master Servicer or the Trustee in respect of
   such Mortgage Loan for which a Mortgage Loan was substituted; and

   (II) the Class B-2 Prepayment Percentage of the Non-PO Recovery for such
   Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class B-2 Optimal Principal Amount
will equal the lesser of (A) the Class B-2 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class B-2 Certificates.

      Class B-2 Percentage: As to any Distribution Date, except as set forth
in the next sentence, the percentage calculated by multiplying (i) the
Subordinated Percentage by (ii) a fraction, the numerator of which is the
Class B-2 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of
the Principal Balances of the Classes of Class B Certificates eligible to
receive principal distributions for such Distribution Date in accordance with
the provisions of Section 4.01(d). Except as set forth in Section
4.01(d)(ii), in the event that the Class B-2 Certificates are not eligible to
receive distributions of principal in accordance with Section 4.01(d)(i), the
Class B-2 Percentage for such Distribution Date will be zero.

      Class B-2 Prepayment Percentage: As to any Distribution Date, except as
set forth in the next sentence, the percentage calculated by multiplying (i)
the Subordinated Prepayment Percentage by (ii) a fraction, the numerator of
which is the Class B-2 Principal Balance (determined as of the Determination
Date preceding such Distribution Date) and the denominator of which is the
sum of the Principal Balances of the Classes of Class B Certificates eligible
to receive principal distributions for such Distribution Date in accordance
with the provisions of Section 4.01(d). Except as set forth in Section
4.01(d)(ii), in the event that the Class B-2 Certificates are not eligible to
receive distributions of principal in accordance with Section 4.01(d)(i), the
Class B-2 Prepayment Percentage for such Distribution Date will be zero.

      Class B-2 Principal Balance: As to the first Determination Date, the
Original Class B-2 Principal Balance. As of any subsequent Determination
Date, the Original Class B-2 Principal Balance less the sum of all amounts
previously distributed in respect of the Class B-2 Certificates on prior
Distribution Dates (A) pursuant to Paragraph tenth of Section 4.01(a)
(including any principal otherwise payable to the Class B-2 Certificates used
to pay any Class A-PO Deferred Amounts) and (B) as a result of a Principal
Adjustment; provided, however, if the Class B-2 Certificates are the most
subordinate Certificates outstanding, the Class B-2 Principal Balance will
equal the difference, if any, between the Adjusted Pool Amount (Non-PO
Portion) as of the preceding Distribution Date less the sum of the Class A
Non-PO Principal Balance and the Class B-1 Principal Balance as of such
Determination Date.

      Class B-2 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class B-2 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed
in respect of the Class B-2 Certificates on prior Distribution Dates pursuant
to Paragraph ninth of Section 4.01(a).

      Class B-3 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially
the form set forth in Exhibit B-3 and Exhibit C hereto.

      Class B-3 Certificateholder: The registered holder of a Class B-3
Certificate.

      Class B-3 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class B-3 Certificates pursuant to
Paragraphs eleventh, twelfth and thirteenth of Section 4.01(a).

      Class B-3 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class B-3 Certificates
with respect to such Distribution Date exceeds the amount distributed in
respect of the Class B-3 Certificates on such Distribution Date pursuant to
Paragraph eleventh of Section 4.01(a).

      Class B-3 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan,
of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan
and (y) the sum of:

      (i) the Class B-3 Percentage of the principal portion of the Monthly
   Payment due on the Due Date occurring in the month of such Distribution
   Date on such Mortgage Loan;

      (ii) the Class B-3 Prepayment Percentage of all Unscheduled Principal
   Receipts (other than Recoveries) that were received by a Servicer with
   respect to such Mortgage Loan during the Applicable Unscheduled Principal
   Receipt Period relating to such Distribution Date for each applicable type
   of Unscheduled Principal Receipt;

      (iii) the Class B-3 Prepayment Percentage of the Scheduled Principal
   Balance of such Mortgage Loan which, during the one month period ending on
   the day preceding the Determination Date for such Distribution Date, was
   repurchased by the Depositor pursuant to Section 2.02, 2.03 or 3.08; and

      (iv) the Class B-3 Percentage of the Substitution Principal Amount with
   respect to each Mortgage Loan for which a Mortgage Loan was substituted
   during the one month period ending on the day preceding the Determination
   Date for such Distribution Date, less the amount allocable to the
   principal portion of any unreimbursed Periodic Advances previously made by
   the applicable Servicer, the Master Servicer or the Trustee in respect of
   such Mortgage Loan for which a Mortgage Loan was substituted; and

   (II) the Class B-3 Prepayment Percentage of the Non-PO Recovery for such
   Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class B-3 Optimal Principal Amount
will equal the lesser of (A) the Class B-3 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class B-3 Certificates.

      Class B-3 Percentage: As to any Distribution Date, except as set forth
in the next sentence, the percentage calculated by multiplying (i) the
Subordinated Percentage by (ii) a fraction, the numerator of which is the
Class B-3 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of
the Principal Balances of the Classes of Class B Certificates eligible to
receive principal distributions for such Distribution Date in accordance with
the provisions of Section 4.01(d). Except as set forth in Section
4.01(d)(ii), in the event that the Class B-3 Certificates are not eligible to
receive distributions of principal in accordance with Section 4.01(d)(i), the
Class B-3 Percentage for such Distribution Date will be zero.

      Class B-3 Prepayment Percentage: As to any Distribution Date, except as
set forth in the next sentence, the percentage calculated by multiplying (i)
the Subordinated Prepayment Percentage by (ii) a fraction, the numerator of
which is the Class B-3 Principal Balance (determined as of the Determination
Date preceding such Distribution Date) and the denominator of which is the
sum of the Principal Balances of the Classes of Class B Certificates eligible
to receive principal distributions for such Distribution Date in accordance
with the provisions of Section 4.01(d). Except as set forth in Section
4.01(d)(ii), in the event that the Class B-3 Certificates are not eligible to
receive distributions of principal in accordance with Section 4.01(d)(i), the
Class B-3 Prepayment Percentage for such Distribution Date will be zero.

      Class B-3 Principal Balance: As to the first Determination Date, the
Original Class B-3 Principal Balance. As of any subsequent Determination
Date, the Original Class B-3 Principal Balance less the sum of all amounts
previously distributed in respect of the Class B-3 Certificates on prior
Distribution Dates (A) pursuant to Paragraph thirteenth of Section 4.01(a)
(including any principal otherwise payable to the Class B-3 Certificates used
to pay any Class A-PO Deferred Amounts) and (B) as a result of a Principal
Adjustment; provided, however, if the Class B-3 Certificates are the most
subordinate Certificates outstanding, the Class B-3 Principal Balance will
equal the difference, if any, between the Adjusted Pool Amount (Non-PO
Portion) as of the preceding Distribution Date less the sum of the Class A
Non-PO Principal Balance, the Class B-1 Principal Balance and the Class B-2
Principal Balance as of such Determination Date.

      Class B-3 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class B-3 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed
in respect of the Class B-3 Certificates on prior Distribution Dates pursuant
to Paragraph twelfth of Section 4.01(a).

      Class B-4 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially
the form set forth in Exhibit B-4 and Exhibit C hereto.

      Class B-4 Certificateholder: The registered holder of a Class B-4
Certificate.

      Class B-4 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class B-4 Certificates pursuant to
Paragraphs fourteenth, fifteenth and sixteenth of Section 4.01(a).

      Class B-4 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class B-4 Certificates
with respect to such Distribution Date exceeds the amount distributed in
respect of the Class B-4 Certificates on such Distribution Date pursuant to
Paragraph fourteenth of Section 4.01(a).

      Class B-4 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan,
of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan
and (y) the sum of:

      (i) the Class B-4 Percentage of the principal portion of the Monthly
   Payment due on the Due Date occurring in the month of such Distribution
   Date on such Mortgage Loan;

      (ii) the Class B-4 Prepayment Percentage of all Unscheduled Principal
   Receipts (other than Recoveries) that were received by a Servicer with
   respect to such Mortgage Loan during the Applicable Unscheduled Principal
   Receipt Period relating to such Distribution Date for each applicable type
   of Unscheduled Principal Receipt;

      (iii) the Class B-4 Prepayment Percentage of the Scheduled Principal
   Balance of such Mortgage Loan which, during the one month period ending on
   the day preceding the Determination Date for such Distribution Date, was
   repurchased by the Depositor pursuant to Section 2.02, 2.03 or 3.08; and

      (iv) the Class B-4 Percentage of the Substitution Principal Amount with
   respect to each Mortgage Loan for which a Mortgage Loan was substituted
   during the one month period ending on the day preceding the Determination
   Date for such Distribution Date, less the amount allocable to the
   principal portion of any unreimbursed Periodic Advances previously made by
   the applicable Servicer, the Master Servicer or the Trustee in respect of
   such Mortgage Loan for which a Mortgage Loan was substituted; and

   (II) the Class B-4 Prepayment Percentage of the Non-PO Recovery for such
   Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class B-4 Optimal Principal Amount
will equal the lesser of (A) the Class B-4 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class B-4 Certificates.

      Class B-4 Percentage: As to any Distribution Date, except as set forth
in the next sentence, the percentage calculated by multiplying (i) the
Subordinated Percentage by (ii) a fraction, the numerator of which is the
Class B-4 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of
the Principal Balances of the Classes of Class B Certificates eligible to
receive principal distributions for such Distribution Date in accordance with
the provisions of Section 4.01(d). Except as set forth in Section
4.01(d)(ii), in the event that the Class B-4 Certificates are not eligible to
receive distributions of principal in accordance with Section 4.01(d)(i), the
Class B-4 Percentage for such Distribution Date will be zero.

      Class B-4 Prepayment Percentage: As to any Distribution Date, except as
set forth in the next sentence, the percentage calculated by multiplying (i)
the Subordinated Prepayment Percentage by (ii) a fraction, the numerator of
which is the Class B-4 Principal Balance (determined as of the Determination
Date preceding such Distribution Date) and the denominator of which is the
sum of the Principal Balances of the Classes of Class B Certificates eligible
to receive principal distributions for such Distribution Date in accordance
with the provisions of Section 4.01(d). Except as set forth in Section
4.01(d)(ii), in the event that the Class B-4 Certificates are not eligible to
receive distributions of principal in accordance with Section 4.01(d)(i), the
Class B-4 Prepayment Percentage for such Distribution Date will be zero.

      Class B-4 Principal Balance: As to the first Determination Date, the
Original Class B-4 Principal Balance. As of any subsequent Determination
Date, the Original Class B-4 Principal Balance less the sum of all amounts
previously distributed in respect of the Class B-4 Certificates on prior
Distribution Dates (A) pursuant to Paragraph sixteenth of Section 4.01(a)
(including any principal otherwise payable to the Class B-4 Certificates used
to pay any Class A-PO Deferred Amounts) and (B) as a result of a Principal
Adjustment; provided, however, if the Class B-4 Certificates are the most
subordinate Certificates outstanding, the Class B-4 Principal Balance will
equal the difference, if any, between the Adjusted Pool Amount (Non-PO
Portion) as of the preceding Distribution Date less the sum of the Class A
Non-PO Principal Balance, the Class B-1 Principal Balance, the Class B-2
Principal Balance and the Class B-3 Principal Balance as of such
Determination Date.

      Class B-4 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class B-4 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed
in respect of the Class B-4 Certificates on prior Distribution Dates pursuant
to Paragraph fifteenth of Section 4.01(a).

      Class B-5 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially
the form set forth in Exhibit B-5 and Exhibit C hereto.

      Class B-5 Certificateholder: The registered holder of a Class B-5
Certificate.

      Class B-5 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class B-5 Certificates pursuant to
Paragraphs seventeenth, eighteenth and nineteenth of Section 4.01(a).

      Class B-5 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class B-5 Certificates
with respect to such Distribution Date exceeds the amount distributed in
respect of the Class B-5 Certificates on such Distribution Date pursuant to
Paragraph seventeenth of Section 4.01(a).

      Class B-5 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan,
of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan
and (y) the sum of:

      (i) the Class B-5 Percentage of the principal portion of the Monthly
   Payment due on the Due Date occurring in the month of such Distribution
   Date on such Mortgage Loan;

      (ii) the Class B-5 Prepayment Percentage of all Unscheduled Principal
   Receipts (other than Recoveries) that were received by a Servicer with
   respect to such Mortgage Loan during the Applicable Unscheduled Principal
   Receipt Period relating to such Distribution Date for each applicable type
   of Unscheduled Principal Receipt;

      (iii) the Class B-5 Prepayment Percentage of the Scheduled Principal
   Balance of such Mortgage Loan which, during the one month period ending on
   the day preceding the Determination Date for such Distribution Date, was
   repurchased by the Depositor pursuant to Section 2.02, 2.03 or 3.08; and

      (iv) the Class B-5 Percentage of the Substitution Principal Amount with
   respect to each Mortgage Loan for which a Mortgage Loan was substituted
   during the one month period ending on the day preceding the Determination
   Date for such Distribution Date, less the amount allocable to the
   principal portion of any unreimbursed Periodic Advances previously made by
   the applicable Servicer, the Master Servicer or the Trustee in respect of
   such Mortgage Loan for which a Mortgage Loan was substituted; and

   (II) the Class B-5 Prepayment Percentage of the Non-PO Recovery for such
   Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class B-5 Optimal Principal Amount
will equal the lesser of (A) the Class B-5 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class B-5 Certificates.

      Class B-5 Percentage: As to any Distribution Date, except as set forth
in the next sentence, the percentage calculated by multiplying (i) the
Subordinated Percentage by (ii) a fraction, the numerator of which is the
Class B-5 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of
the Principal Balances of the Classes of Class B Certificates eligible to
receive principal distributions for such Distribution Date in accordance with
the provisions of Section 4.01(d). Except as set forth in Section
4.01(d)(ii), in the event that the Class B-5 Certificates are not eligible to
receive distributions of principal in accordance with Section 4.01(d)(i), the
Class B-5 Percentage for such Distribution Date will be zero.

      Class B-5 Prepayment Percentage: As to any Distribution Date, except as
set forth in the next sentence, the percentage calculated by multiplying (i)
the Subordinated Prepayment Percentage by (ii) a fraction, the numerator of
which is the Class B-5 Principal Balance (determined as of the Determination
Date preceding such Distribution Date) and the denominator of which is the
sum of the Principal Balances of the Classes of Class B Certificates eligible
to receive principal distributions for such Distribution Date in accordance
with the provisions of Section 4.01(d). Except as set forth in Section
4.01(d)(ii), in the event that the Class B-5 Certificates are not eligible to
receive distributions of principal in accordance with Section 4.01(d)(i), the
Class B-5 Prepayment Percentage for such Distribution Date will be zero.

      Class B-5 Principal Balance: As to the first Determination Date, the
Original Class B-5 Principal Balance. As of any subsequent Determination
Date, the Original Class B-5 Principal Balance less the sum of all amounts
previously distributed in respect of the Class B-5 Certificates on prior
Distribution Dates (A) pursuant to Paragraph nineteenth of Section 4.01(a)
(including any principal otherwise payable to the Class B-5 Certificates used
to pay any Class A-PO Deferred Amounts) and (B) as a result of a Principal
Adjustment; provided, however, if the Class B-5 Certificates are the most
subordinate Certificates outstanding, the Class B-5 Principal Balance will
equal the difference, if any, between the Adjusted Pool Amount (Non-PO
Portion) as of the preceding Distribution Date less the sum of the Class A
Non-PO Principal Balance, the Class B-1 Principal Balance, the Class B-2
Principal Balance, the Class B-3 Principal Balance and the Class B-4
Principal Balance as of such Determination Date.

      Class B-5 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class B-5 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed
in respect of the Class B-5 Certificates on prior Distribution Dates pursuant
to Paragraph eighteenth of Section 4.01(a).

      Class B-6 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially
the form set forth in Exhibit B-6 and Exhibit C hereto.

      Class B-6 Certificateholder: The registered holder of a Class B-6
Certificate.

      Class B-6 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class B-6 Certificates pursuant to
Paragraphs twentieth, twenty-first and twenty-second of Section 4.01(a).

      Class B-6 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class B-6 Certificates
with respect to such Distribution Date exceeds the amount distributed in
respect of the Class B-6 Certificates on such Distribution Date pursuant to
Paragraph twentieth of Section 4.01(a).

      Class B-6 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan,
of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan
and (y) the sum of:

      (i) the Class B-6 Percentage of the principal portion of the Monthly
   Payment due on the Due Date occurring in the month of such Distribution
   Date on such Mortgage Loan;

      (ii) the Class B-6 Prepayment Percentage of all Unscheduled Principal
   Receipts (other than Recoveries) that were received by a Servicer with
   respect to such Mortgage Loan during the Applicable Unscheduled Principal
   Receipt Period relating to such Distribution Date for each applicable type
   of Unscheduled Principal Receipt;

      (iii) the Class B-6 Prepayment Percentage of the Scheduled Principal
   Balance of such Mortgage Loan which, during the one month period ending on
   the day preceding the Determination Date for such Distribution Date, was
   repurchased by the Depositor pursuant to Section 2.02, 2.03 or 3.08; and

      (iv) the Class B-6 Percentage of the Substitution Principal Amount with
   respect to each Mortgage Loan for which a Mortgage Loan was substituted
   during the one month period ending on the day preceding the Determination
   Date for such Distribution Date, less the amount allocable to the
   principal portion of any unreimbursed Periodic Advances previously made by
   the applicable Servicer, the Master Servicer or the Trustee in respect of
   such Mortgage Loan for which a Mortgage Loan was substituted; and

   (II) the Class B-6 Prepayment Percentage of the Non-PO Recovery for such
   Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class B-6 Optimal Principal Amount
will equal the lesser of (A) the Class B-6 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class B-6 Certificates.

      Class B-6 Percentage: As to any Distribution Date, except as set forth
in the next sentence, the percentage calculated by multiplying (i) the
Subordinated Percentage by (ii) a fraction, the numerator of which is the
Class B-6 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of
the Principal Balances of the Classes of Class B Certificates eligible to
receive principal distributions for such Distribution Date in accordance with
the provisions of Section 4.01(d). Except as set forth in Section
4.01(d)(ii), in the event that the Class B-6 Certificates are not eligible to
receive distributions of principal in accordance with Section 4.01(d)(i), the
Class B-6 Percentage for such Distribution Date will be zero.

      Class B-6 Prepayment Percentage: As to any Distribution Date, except as
set forth in the next sentence, the percentage calculated by multiplying (i)
the Subordinated Prepayment Percentage by (ii) a fraction, the numerator of
which is the Class B-6 Principal Balance (determined as of the Determination
Date preceding such Distribution Date) and the denominator of which is the
sum of the Principal Balances of the Classes of Class B Certificates eligible
to receive principal distributions for such Distribution Date in accordance
with the provisions of Section 4.01(d). Except as set forth in Section
4.01(d)(ii), in the event that the Class B-6 Certificates are not eligible to
receive distributions of principal in accordance with Section 4.01(d)(i), the
Class B-6 Prepayment Percentage for such Distribution Date will be zero.

      Class B-6 Principal Balance: As to the first Determination Date, the
Original Class B-6 Principal Balance. As of any subsequent Determination
Date, for so long as the Class B-6 Certificates are outstanding, the
difference, if any, between the Adjusted Pool Amount (Non-PO Portion) as of
the preceding Distribution Date less the sum of the Class A Non-PO Principal
Balance, the Class B-1 Principal Balance, the Class B-2 Principal Balance,
the Class B-3 Principal Balance, the Class B-4 Principal Balance and the
Class B-5 Principal Balance as of such Determination Date.

      Class B-6 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class B-6 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed
in respect of the Class B-6 Certificates on prior Distribution Dates pursuant
to Paragraph twenty-first of Section 4.01(a).

      Clearing Agency: An organization registered as a "clearing agency"
pursuant to Section 17A of the Exchange Act. The initial Clearing Agency
shall be DTC.

      Clearing Agency Participant: A broker, dealer, bank, financial
institution or other Person for whom a Clearing Agency effects book-entry
transfers of securities deposited with the Clearing Agency.

      Closing Date: The date of initial issuance of the Certificates, as set
forth in Section 11.20.

      Code: The Internal Revenue Code of 1986, as it may be amended from time
to time, any successor statutes thereto, and applicable U.S. Department of
the Treasury temporary or final regulations promulgated thereunder.

      Combination Group: Each Exchangeable Combination and Exchangeable REMIC
Combination having the same numerical designation as set forth on Exhibit W.

      Commission: The United States Securities and Exchange Commission.

      Compensating Interest: With respect to any Distribution Date, the least
of (a) the aggregate Prepayment Interest Shortfall on the Mortgage Loans for
such Distribution Date, (b) the product of (i) 1/12th of 0.20% and (ii) the
Pool Scheduled Principal Balance for such Distribution Date and (c) the
Available Master Servicing Compensation for such Distribution Date.

      Co-op Shares: Shares issued by private non-profit housing corporations.

      Corporate Trust Office: With respect to (a) the Trustee, the office of
the Trustee at which at any particular time its duties under this Agreement
shall be administered, which office, at the date of the execution of this
instrument, is located at 452 Fifth Avenue, New York, New York 10018,
Attention: CTLA - Structured Finance, WFMBS 2007-17 and (b) the Paying Agent,
Certificate Registrar and Authenticating Agent, for Certificate transfer
purposes at Wells Fargo Center, Sixth Street and Marquette Avenue,
Minneapolis, Minnesota 55479 Attn: Corporate Trust Services--WFMBS 2007-17,
and for all other purposes at 9062 Old Annapolis Road, Columbia, Maryland
21045 Attn: Corporate Trust Services--WFMBS 2007-17.

      Current Class A Interest Distribution Amount: As to any Distribution
Date, the amount distributed in respect of the Classes of Class A
Certificates pursuant to Paragraph first of Section 4.01(a) on such
Distribution Date.

      Current Class B Interest Distribution Amount: As to any Distribution
Date, the amount distributed in respect of the Classes of Class B
Certificates pursuant to Paragraphs fifth, eighth, eleventh, fourteenth,
seventeenth and twentieth of Section 4.01(a) on such Distribution Date.

      Current Class B-1 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by
dividing the sum of the Principal Balances of the Class B-2, Class B-3, Class
B-4, Class B-5 and Class B-6 Certificates by the Aggregate Non-PO Principal
Balance. As to the first Distribution Date, the Original Class B-1 Fractional
Interest.

      Current Class B-2 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by
dividing the sum of the Principal Balances of the Class B-3, Class B-4, Class
B-5 and Class B-6 Certificates by the Aggregate Non-PO Principal Balance. As
to the first Distribution Date, the Original Class B-2 Fractional Interest.

      Current Class B-3 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by
dividing the sum of the Principal Balances of the Class B-4, Class B-5 and
Class B-6 Certificates by the Aggregate Non-PO Principal Balance. As to the
first Distribution Date, the Original Class B-3 Fractional Interest.

      Current Class B-4 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by
dividing the sum of the Principal Balances of the Class B-5 and Class B-6
Certificates by the Aggregate Non-PO Principal Balance. As to the first
Distribution Date, the Original Class B-4 Fractional Interest.

      Current Class B-5 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by
dividing the Principal Balance of the Class B-6 Certificates by the Aggregate
Non-PO Principal Balance. As to the first Distribution Date, the Original
Class B-5 Fractional Interest.

      Curtailment: Any Principal Prepayment made by a Mortgagor which is not
a Prepayment in Full.

      Curtailment Interest Shortfall: On any Distribution Date with respect
to a Mortgage Loan which was the subject of a Curtailment:

      (A)   in the case where the Applicable Unscheduled Principal Receipt
            Period is the Mid-Month Receipt Period and such Curtailment is
            received by the applicable Servicer on or after the Determination
            Date in the month preceding the month of such Distribution Date but
            prior to the first day of the month of such Distribution Date, the
            amount of interest that would have accrued at the Net Mortgage
            Interest Rate on the amount of such Curtailment from the day of its
            receipt or, if earlier, its application by such Servicer through the
            last day of the month preceding the month of such Distribution Date;
            and

      (B)   in the case where the Applicable Unscheduled Principal Receipt
            Period is the Prior Month Receipt Period and such Curtailment is
            received by the applicable Servicer during the month preceding the
            month of such Distribution Date, the amount of interest that would
            have accrued at the Net Mortgage Interest Rate on the amount of such
            Curtailment from the day of its receipt or, if earlier, its
            application by such Servicer through the last day of the month in
            which such Curtailment is received.

      CUSIP Number: With respect to each Certificate, the identification
number provided by the CUSIP Service Bureau and appearing on the face of such
Certificate.

      Custodial Agreement: The Custodial Agreement, dated as of December 20,
2007, among the Custodian, the Depositor, the Master Servicer and the
Trustee, which agreement is attached hereto as Exhibit E, as the same may be
amended or modified from time to time in accordance with the terms thereof.

      Custodial P&I Account: The Custodial P&I Account, as defined in each of
the Servicing Agreements, with respect to the Mortgage Loans. In determining
whether the Custodial P&I Account under any Servicing Agreement is
"acceptable" to the Master Servicer (as may be required by the definition of
"Eligible Account" contained in the Servicing Agreements), the Master
Servicer shall require that any such account shall be acceptable to each of
the Rating Agencies.

      Custodian: Wells Fargo Bank, or its successor in interest under the
Custodial Agreement. Initially, the custodial functions shall be performed by
the Corporate Trust Services division of Wells Fargo Bank.

      Cut-Off Date: The first day of the month of initial issuance of the
Certificates as set forth in Section 11.01.

      Cut-Off Date Aggregate Principal Balance: The aggregate of the Cut-Off
Date Principal Balances of the Mortgage Loans as set forth in Section 11.02.

      Cut-Off Date Principal Balance: As to each Mortgage Loan, its unpaid
principal balance as of the close of business on the Cut-Off Date (but
without giving effect to any Unscheduled Principal Receipts received or
applied on the Cut-Off Date), reduced by all payments of principal due on or
before the Cut-Off Date and not paid, and increased by scheduled monthly
payments of principal due after the Cut-Off Date but received by the related
Servicer on or before the Cut-Off Date.

      Debt Service Reduction: With respect to any Mortgage Loan, a reduction
in the scheduled Monthly Payment for such Mortgage Loan by a court of
competent jurisdiction in a proceeding under the Bankruptcy Code, except such
a reduction constituting a Deficient Valuation.

      Deficient Valuation: With respect to any Mortgage Loan, a valuation by
a court of competent jurisdiction of the Mortgaged Property in an amount less
than the then-outstanding indebtedness under the Mortgage Loan, or any
reduction in the amount of principal to be paid in connection with any
scheduled Monthly Payment that results in a permanent forgiveness of
principal, which valuation or reduction results from a proceeding under the
Bankruptcy Code.

      Definitive Certificates: As defined in Section 5.01(b).

      Denomination: The amount, if any, specified on the face of each
Certificate of a Class representing the principal portion of the Original
Principal Balance or, in the case of a Class of Exchangeable REMIC
Certificates or Exchangeable Certificates, the Maximum Initial Principal
Balance of such Class evidenced by such Certificate.

      Depositor: Wells Fargo Asset Securities Corporation, or its successor
in interest.

      DTC: The Depository Trust Company, or its successor in interest.

      Determination Date: The 17th day of the month in which the related
Distribution Date occurs, or if such 17th day is not a Business Day, the
Business Day preceding such 17th day.

      Discount Mortgage Loan: A Mortgage Loan with a Net Mortgage Interest
Rate of less than 6.000%.

      Distribution Date: The 25th day of any month, beginning in the month
following the month of initial issuance of the Certificates, or if such 25th
day is not a Business Day, the Business Day following such 25th day.

      Distribution Date Statement: As defined in Section 4.04(a).

      Document Transfer Date: The 60th day following the occurrence of a
Document Transfer Event.

      Document Transfer Event: The occurrence of either of the following: (i)
Wells Fargo Bank is no longer the Servicer of any of the Mortgage Loans or
(ii) the senior, unsecured long-term debt rating of Wells Fargo & Company is
less than "BBB-" by Fitch.

      Due Date: With respect to any Mortgage Loan, the day of the month in
which the Monthly Payment on such Mortgage Loan is scheduled to be paid.

      Eligible Account: One or more accounts (i) that are maintained with a
depository institution (which may be the Master Servicer) whose long-term
debt obligations (or, in the case of a depository institution which is part
of a holding company structure, the long-term debt obligations of such parent
holding company) at the time of deposit therein are rated at least "AA" (or
the equivalent) by each Rating Agency, (ii) that are trust accounts
maintained with the trust department of a federal or state chartered
depository institution or trust company acting in its fiduciary capacity or
(iii) such other account that is acceptable to each of the Rating Agencies
and would not cause the REMIC to fail to qualify as a REMIC or result in the
imposition of any federal tax on the REMIC. If an account ceases to be an
Eligible Account under clause (i) and does not otherwise qualify under clause
(ii) or (iii) the account will be moved within 30 days to a depository
meeting the ratings criteria.

      Eligible Investments: At any time, any one or more of the following
obligations and securities which shall mature not later than the Business Day
preceding the Distribution Date next succeeding the date of such investment,
provided that such investments continue to qualify as "cash flow investments"
as defined in Code Section 860G(a)(6):

      (i) obligations of the United States of America or any agency thereof,
   provided such obligations are backed by the full faith and credit of the
   United States of America;

      (ii) general obligations of or obligations guaranteed by any state of
   the United States of America or the District of Columbia receiving the
   highest short-term or highest long-term rating of each Rating Agency, or
   such lower rating as would not result in the downgrading or withdrawal of
   the rating then assigned to any of the Certificates by any Rating Agency
   or result in any of such rated Certificates being placed on credit review
   status (other than for possible upgrading) by any Rating Agency;

      (iii) commercial or finance company paper which is then rated in the
   highest long-term commercial or finance company paper rating category of
   each Rating Agency or the highest short-term rating category of each
   Rating Agency, or such lower rating category as would not result in the
   downgrading or withdrawal of the rating then assigned to any of the
   Certificates by any Rating Agency or result in any of such rated
   Certificates being placed on credit review status (other than for possible
   upgrading) by any Rating Agency;

      (iv) certificates of deposit, demand or time deposits, federal funds or
   banker's acceptances issued by any depository institution or trust company
   incorporated under the laws of the United States or of any state thereof
   and subject to supervision and examination by federal and/or state banking
   authorities, provided that the commercial paper and/or debt obligations of
   such depository institution or trust company (or in the case of the
   principal depository institution in a holding company system, the
   commercial paper or debt obligations of such holding company) are then
   rated in the highest short-term or the highest long-term rating category
   for such securities of each of the Rating Agencies, or such lower rating
   categories as would not result in the downgrading or withdrawal of the
   rating then assigned to any of the Certificates by any Rating Agency or
   result in any of such rated Certificates being placed on credit review
   status (other than for possible upgrading) by any Rating Agency;

      (v) guaranteed reinvestment agreements issued by any bank, insurance
   company or other corporation acceptable to each Rating Agency at the time
   of the issuance of such agreements;

      (vi) repurchase agreements on obligations with respect to any security
   described in clauses (i) or (ii) above or any other security issued or
   guaranteed by an agency or instrumentality of the United States of
   America, in either case entered into with a depository institution or
   trust company (acting as principal) described in (iv) above;

      (vii) securities (other than stripped bonds or stripped coupon
   securities) bearing interest or sold at a discount issued by any
   corporation incorporated under the laws of the United States of America or
   any state thereof which, at the time of such investment or contractual
   commitment providing for such investment, are then rated in the highest
   short-term or the highest long-term rating category by each Rating Agency,
   or in such lower rating category as would not result in the downgrading or
   withdrawal of the rating then assigned to any of the Certificates by any
   Rating Agency or result in any of such rated Certificates being placed on
   credit review status (other than for possible upgrading) by any Rating
   Agency;

      (viii) such other investments acceptable to each Rating Agency as would
   not result in the downgrading of the rating then assigned to the
   Certificates by any Rating Agency or result in any of such rated
   Certificates being placed on credit review status (other than for possible
   upgrading) by any Rating Agency; and

      (ix)  any mutual fund, money market fund, common trust fund or other
   pooled investment vehicle, the assets of which are limited to instruments
   that otherwise would constitute Eligible Investments hereunder, including
   any such fund that is managed by the Trustee or Master Servicer or any
   affiliate of the Trustee or Master Servicer or for which the Trustee or
   Master Servicer or any of its affiliates acts as an adviser as long as
   such fund is rated in at least the highest rating category by each Rating
   Agency rating such fund.

      In no event shall an instrument be an Eligible Investment if such
instrument evidences either (i) a right to receive only interest payments
with respect to the obligations underlying such instrument, or (ii) both
principal and interest payments derived from obligations underlying such
instrument and the interest and principal payments with respect to such
instrument provide a yield to maturity at the date of investment of greater
than 120% of the yield to maturity at par of such underlying obligations.

      ERISA: The Employee Retirement Income Security Act of 1974, as amended.

      ERISA Prohibited Holder: As defined in Section 5.02(d).

      Errors and Omissions Policy: As defined in each of the Servicing
Agreements.

      Event of Default: Any of the events specified in Section 7.01.

      Exchange Act: The Securities Exchange Act of 1934, as amended.

      Exchangeable Certificate Grantor Trust Account: The sub-account of the
Certificate Account designated by the Master Servicer pursuant to Section
4.05.

      Exchangeable Certificates: The Class A-1 Certificates.

      Exchangeable Classes: The Class or Classes of Exchangeable Certificates.

      Exchangeable Combination: Exchangeable Combination 1.

      Exchangeable Combination 1: The Class A-1 Certificates.

      Exchangeable REMIC Certificates: The Class A-2 and Class A-3
Certificates.

      Exchangeable REMIC Classes: The Class or Classes of Exchangeable REMIC
Certificates.

      Exchangeable REMIC Combination: Exchangeable REMIC Combination 1.

      Exchangeable REMIC Combination 1: The Class A-2 and Class A-3
Certificates.

      FDIC: The Federal Deposit Insurance Corporation or any successor
thereto.

      Fidelity Bond: As defined in each of the Servicing Agreements.

      Final Distribution Date: The Distribution Date on which the final
distribution in respect of the Certificates is made pursuant to Section 9.01.

      Final Scheduled Maturity Date: The Final Scheduled Maturity Date for
each Class of Class A Certificates and Class B Certificates is January 25,
2038, which corresponds to the "latest possible maturity date" for purposes
of Section 860G(a)(1) of the Internal Revenue Code of 1986, as amended.

      Fitch: Fitch Ratings, or its successor in interest.

      Fixed Retained Yield: The fixed percentage of interest on each Mortgage
Loan with a Mortgage Interest Rate greater than the sum of (a) 6.000%,
(b) the applicable Servicing Fee Rate and (c) the Master Servicing Fee Rate,
which will be determined on a loan by loan basis and will equal the Mortgage
Interest Rate on each Mortgage Loan minus the sum of the rates described in
clauses (a), (b) and (c), which is not assigned to and not part of the Trust
Estate.

      Fixed Retained Yield Rate: With respect to each Mortgage Loan, a per
annum rate equal to the greater of (a) zero and (b) the Mortgage Interest
Rate on such Mortgage Loan minus, the sum of (a) 6.000%, (b) the applicable
Servicing Fee Rate and (c) the Master Servicing Fee Rate.

      Form 8-K: A Current Report on Form 8-K under the Exchange Act.

      Form 8-K Disclosure Information: As defined in Section 3.12(c).

      Form 10-D: An Asset-Backed Issuer Distribution Report on Form 10-D
under the Exchange Act.

      Form 10-K: An Annual Report on Form 10-K under the Exchange Act.

      Form 15: A Form 15 Suspension Notification under the Exchange Act.

      Full Unscheduled Principal Receipt: Any Unscheduled Principal Receipt
with respect to a Mortgage Loan (i) in the amount of the outstanding
principal balance of such Mortgage Loan and resulting in the full
satisfaction of such Mortgage Loan or (ii) representing Liquidation Proceeds
other than Partial Liquidation Proceeds.

      Grantor Trust: That portion of the Trust exclusive of the REMIC
consisting of any interests in the Exchangeable REMIC Certificates
beneficially owned in the form of Exchangeable Certificates and rights with
respect thereto.

      Holder: See "Certificateholder."

      Independent: When used with respect to any specified Person, such
Person who (i) is in fact independent of the Depositor, the Master Servicer
and any Servicer, (ii) does not have any direct financial interest or any
material indirect financial interest in the Depositor or the Master Servicer
or any Servicer or in an affiliate of either and (iii) is not connected with
the Depositor, the Master Servicer or any Servicer as an officer, employee,
promoter, underwriter, trustee, partner, director or person performing
similar functions.

      Insurance Policy: Any insurance or performance bond relating to a
Mortgage Loan or the Mortgage Loans, including any hazard insurance, special
hazard insurance, flood insurance, primary mortgage insurance, mortgagor
bankruptcy bond or title insurance.

      Insurance Proceeds: Proceeds paid by any insurer pursuant to any
Insurance Policy covering a Mortgage Loan.

      Insured Expenses: Expenses covered by any Insurance Policy covering a
Mortgage Loan.

      Interest Accrual Amount: As to any Distribution Date and any Class of
Class A Certificates (other than the Classes of Principal Only and
Exchangeable Certificates), (i) the product of (a) 1/12th of the Class A
Pass-Through Rate for such Class and (b) the Principal Balance of such Class
as of the Determination Date immediately preceding such Distribution Date
minus (ii) the sum of (A) the Class A Interest Percentage of such Class of
the interest portion of any Realized Losses on the Mortgage Loans on or after
the Subordination Depletion Date pursuant to Section 4.02(c) and (B) the
Class A Interest Percentage of such Class of any Non-Supported Interest
Shortfall or Relief Act Shortfall allocated to the Class A Certificates with
respect to such Distribution Date. The Principal Only Certificates and
Exchangeable Certificates have no Interest Accrual Amount.

      As to any Distribution Date and any Class of Class B Certificates, an
amount equal to (i) the product of (a) 1/12th of the Class B Pass-Through
Rate and (b) the Principal Balance of such Class as of the Determination Date
preceding such Distribution Date minus (ii) the Class B Interest Percentage
of such Class of the sum of any Non-Supported Interest Shortfall and any
Relief Act Shortfall allocated to the Class B Certificates with respect to
such Distribution Date.

      Liquidated Loan: A Mortgage Loan with respect to which the related
Mortgaged Property has been acquired, liquidated or foreclosed and with
respect to which the applicable Servicer determines that all Liquidation
Proceeds which it expects to recover have been recovered.

      Liquidated Loan Loss: With respect to any Distribution Date, the
aggregate of the amount of losses with respect to each Mortgage Loan which
became a Liquidated Loan during the Applicable Unscheduled Principal Receipt
Period with respect to Full Unscheduled Principal Receipts for such
Distribution Date, equal to the excess of (i) the unpaid principal balance of
each such Liquidated Loan, plus accrued interest thereon in accordance with
the amortization schedule at the time applicable thereto at the applicable
Net Mortgage Interest Rate from the Due Date as to which interest was last
paid with respect thereto through the last day of the month preceding the
month in which such Distribution Date occurs, over (ii) Net Liquidation
Proceeds with respect to such Liquidated Loan.

      Liquidation Expenses: Expenses incurred by a Servicer in connection
with the liquidation of any defaulted Mortgage Loan or property acquired in
respect thereof (including, without limitation, legal fees and expenses,
committee or referee fees, and, if applicable, brokerage commissions and
conveyance taxes), any unreimbursed advances (including Periodic Advances)
expended by such Servicer pursuant to its Servicing Agreement or the Master
Servicer or Trustee pursuant hereto respecting the related Mortgage Loan,
including any unreimbursed advances for real property taxes or for property
restoration or preservation of the related Mortgaged Property. Liquidation
Expenses shall not include any previously incurred expenses in respect of an
REO Mortgage Loan which have been netted against related REO Proceeds.

      Liquidation Proceeds: Amounts received by a Servicer (including
Insurance Proceeds) or PMI Advances made by a Servicer in connection with the
liquidation of defaulted Mortgage Loans or property acquired in respect
thereof, whether through foreclosure, sale or otherwise, including payments
in connection with such Mortgage Loans received from the Mortgagor, other
than amounts required to be paid to the Mortgagor pursuant to the terms of
the applicable Mortgage or to be applied otherwise pursuant to law.

      Liquidation Profits: As to any Distribution Date and any Mortgage Loan
that became a Liquidated Loan during the Applicable Unscheduled Principal
Receipt Period with respect to Full Unscheduled Principal Receipts for such
Distribution Date, the excess, if any, of (i) Net Liquidation Proceeds in
respect of such Liquidated Loan over (ii) the unpaid principal balance of
such Liquidated Loan plus accrued interest thereon in accordance with the
amortization schedule at the time applicable thereto at the applicable Net
Mortgage Interest Rate from the Due Date to which interest was last paid with
respect thereto through the last day of the month preceding the month in
which such Distribution Date occurs.

      Loan-to-Value Ratio: The ratio, expressed as a percentage, the
numerator of which is the principal balance of a particular Mortgage Loan at
origination and the denominator of which is the lesser of (x) the appraised
value of the related Mortgaged Property determined in the appraisal used by
the originator at the time of origination (or prior to origination if
permitted by the Underwriting Guidelines) of such Mortgage Loan, and (y) if
the Mortgage is originated in connection with a sale of the Mortgaged
Property, the sale price for such Mortgaged Property.

      Master Servicer: Wells Fargo Bank, or its successor in interest.
Initially, the Master Servicer functions shall be performed by the Corporate
Trust Services division of Wells Fargo Bank.

      Master Servicer Errors and Omissions Policy: An insurance policy
covering losses caused by errors or omissions of the Master Servicer and its
personnel.

      Master Servicing Fee: With respect to any Mortgage Loan and any
Distribution Date, the fee payable monthly to the Master Servicer pursuant to
Section 6.05 equal to the product of one-twelfth of the Master Servicing Fee
Rate and the unpaid principal balance of such Mortgage Loan.

      Master Servicing Fee Rate: As set forth in Section 11.24.

      Master Servicing Officer: Any officer of the Master Servicer involved
in, or responsible for, the administration and master servicing of the
Mortgage Loans.

      Maximum Initial Principal Balance: As to each Class of Exchangeable
REMIC Certificates and Exchangeable Certificates, the Maximum Initial
Principal Balance for such Class set forth in Section 11.05.

      Maximum Principal Balance: As of any Determination Date and Class of
Exchangeable Certificates, the portion of the Maximum Initial Principal
Balance that would be outstanding on any date assuming all Related
Exchangeable REMIC Certificates had been exchanged on the Closing Date.

      MERS: The Mortgage Electronic Registration Systems, Inc.

      MERS Mortgage Loan: Any MOM Mortgage Loan or any other Mortgage Loan as
to which MERS is (or is intended to be) the mortgagee of record and as to
which a MIN has been assigned.

      Mid-Month Receipt Period: With respect to each Distribution Date, the
one month period beginning on the Determination Date (or, in the case of the
first Distribution Date, from and including the Cut-Off Date) occurring in
the calendar month preceding the month in which such Distribution Date occurs
and ending on the day preceding the Determination Date immediately preceding
such Distribution Date.

      MIN: A MERS Mortgage Identification Number assigned to a Mortgage Loan
registered under MERS.

      MOM: A Mortgage Loan where the related Mortgage names MERS as the
original mortgagee thereof, as to which a MIN has been assigned, and which
Mortgage has not been assigned to any other person.

      Month End Interest: As defined in each Servicing Agreement.

      Monthly Payment: As to any Mortgage Loan (including any REO Mortgage
Loan) and any Due Date, the monthly interest payment or the scheduled monthly
payment of principal due thereon in accordance with the amortization schedule
at the time applicable thereto (after adjustment for any Curtailments and
Deficient Valuations occurring prior to such Due Date but before any
adjustment to such amortization schedule, other than for Deficient
Valuations, by reason of any bankruptcy or similar proceeding or any
moratorium or similar waiver or grace period).

      Moody's: Moody's Investors Service, Inc. or its successor in interest.

      Mortgage: The mortgage, deed of trust or other instrument creating a
first lien on Mortgaged Property securing a Mortgage Note together with any
Mortgage Loan Rider, if applicable.

      Mortgage Interest Rate: As to any Mortgage Loan, the per annum rate at
which interest accrues on the unpaid principal balance thereof as set forth
in the related Mortgage Note, which rate is as indicated on the Mortgage Loan
Schedule.

      Mortgage Loan Purchase Agreement: The mortgage loan purchase agreement
dated as of December 20, 2007 between Wells Fargo Bank, as seller, and the
Depositor, as purchaser.

      Mortgage Loan Rider: The standard Fannie Mae/Freddie Mac riders to the
Mortgage Note and/or Mortgage riders required when the Mortgaged Property is
a condominium unit or a unit in a planned unit development.

      Mortgage Loan Schedule: The list delivered by the Depositor to the
Trustee, the Master Servicer and the Custodian of the Mortgage Loans
transferred to the Trustee on the Closing Date as part of the Trust Estate,
which list may be amended following the Closing Date upon conveyance of a
Substitute Mortgage Loan pursuant to Section 2.02 or 2.03 and which list
shall set forth at a minimum the following information as of the close of
business on the Cut-Off Date (or, with respect to Substitute Mortgage Loans,
as of the close of business on the day of substitution) as to each Mortgage
Loan:

      (i) the Mortgage Loan identifying number;

      (ii) the city, state and zip code of the Mortgaged Property;

      (iii) the type of property;

      (iv) the Mortgage Interest Rate;

      (v) the Net Mortgage Interest Rate;

      (vi) the Monthly Payment;

      (vii) the original number of months to maturity;

      (viii) the scheduled maturity date;

      (ix) the Cut-Off Date Principal Balance;

      (x) the Loan-to-Value Ratio at origination;

      (xi) whether such Mortgage Loan is a Subsidy Loan;

      (xii) whether such Mortgage Loan is covered by primary mortgage
   insurance;

      (xiii) the applicable Servicing Fee Rate;

      (xiv) the Master Servicing Fee Rate;

      (xv)  the Fixed Retained Yield Rate, if applicable;

      (xvi) in the case of any Mortgage Loan initially serviced by Wells Fargo
   Bank, whether such Mortgage Loan is a Type 1 Mortgage Loan or a Type 2
   Mortgage Loan; and

      (xvii) the name of the Servicer.

      Such schedule may consist of multiple reports that collectively set
forth all of the information required.

      Mortgage Loans: Each of the mortgage loans transferred and assigned to
the Trustee on the Closing Date pursuant to Section 2.01(a) and any mortgage
loans substituted therefor pursuant to Section 2.02 or 2.03, in each case as
from time to time are included in the Trust Estate as identified in the
Mortgage Loan Schedule.

      Mortgage Note: The note or other evidence of indebtedness evidencing
the indebtedness of a Mortgagor under a Mortgage Loan together with any
related Mortgage Loan Riders, if applicable.

      Mortgaged Property: The property subject to a Mortgage, which may
include Co-op Shares or residential long-term leases.

      Mortgagor: The obligor on a Mortgage Note.

      Net Liquidation Proceeds: As to any defaulted Mortgage Loan,
Liquidation Proceeds net of Liquidation Expenses.

      Net Mortgage Interest Rate: With respect to each Mortgage Loan, a rate
equal to (i) the Mortgage Interest Rate on such Mortgage Loan minus (ii) the
sum of (a) the applicable Servicing Fee Rate, as set forth in Section 11.23
with respect to such Mortgage Loan, (b) the Master Servicing Fee Rate, as set
forth in Section 11.24 with respect to such Mortgage Loan and (c) the Fixed
Retained Yield Rate, if any, with respect to such Mortgage Loan. Any regular
monthly computation of interest at such rate shall be based upon annual
interest at such rate on the applicable amount divided by twelve.

      Net REO Proceeds: As to any REO Mortgage Loan, REO Proceeds net of any
related expenses of the applicable Servicer.

      Non-permitted Foreign Holder: As defined in Section 5.02(d).

      Non-PO Fraction: With respect to any Mortgage Loan, the lesser of
(i) 1.00 and (ii) the quotient obtained by dividing the Net Mortgage Interest
Rate for such Mortgage Loan by 6.000%.

      Non-PO Recovery: As to any Distribution Date, the amount of all
Recoveries received during the Applicable Unscheduled Principal Receipt
Periods for such Distribution Date less the Class A-PO Recovery for such
Distribution Date.

      Nonrecoverable Advance: Any portion of a Periodic Advance previously
made or proposed to be made in respect of a Mortgage Loan which has not been
previously reimbursed to the applicable Servicer, the Master Servicer or the
Trustee, as the case may be, and which the applicable Servicer, the Master
Servicer or the Trustee determines will not, or in the case of a proposed
Periodic Advance would not, be ultimately recoverable from Liquidation
Proceeds or other recoveries in respect of the related Mortgage Loan. The
determination by the applicable Servicer, the Master Servicer or the Trustee
(i) that it has made a Nonrecoverable Advance or (ii) that any proposed
Periodic Advance, if made, would constitute a Nonrecoverable Advance, shall
be evidenced by an Officer's Certificate of such Servicer delivered to the
Master Servicer for redelivery to the Trustee or, in the case of a Master
Servicer determination, an Officer's Certificate of the Master Servicer
delivered to the Trustee, in each case detailing the reasons for such
determination.

      Non-Supported Interest Shortfall: With respect to any Distribution
Date, the sum of (i) the excess, if any, of the aggregate Prepayment Interest
Shortfall on the Mortgage Loans over the aggregate Compensating Interest with
respect to such Distribution Date and (ii) Curtailment Interest Shortfalls
with respect to such Distribution Date. With respect to each Distribution
Date occurring on or after the Subordination Depletion Date, the
Non-Supported Interest Shortfall determined pursuant to the preceding
sentence will be increased by the amount of any Subordination Depletion Date
Interest Shortfall for such Distribution Date. Any Non-Supported Interest
Shortfall will be allocated to (a) the Class A Non-PO Certificates according
to the percentage obtained by dividing the Class A Non-PO Principal Balance
by the Aggregate Non-PO Principal Balance and (b) the Class B Certificates
according to the percentage obtained by dividing the Class B Principal
Balance by the Aggregate Non-PO Principal Balance.

      Non-U.S. Person: As defined in Section 4.01(f).

      NYCEMA: A New York Consolidation, Extension and Modification Agreement.

      Officer's Certificate: With respect to any Person, a certificate signed
by the Chairman of the Board, the President or a Vice President, and by the
Treasurer, the Secretary or one of the Assistant Treasurers, Assistant
Secretaries or any other duly authorized officer of such Person (or, in the
case of a Person which is not a corporation, signed by the person or persons
having like responsibilities).

      Opinion of Counsel: A written opinion of counsel, who may be outside or
salaried counsel for the Depositor, a Servicer or the Master Servicer, or any
affiliate of the Depositor, a Servicer or the Master Servicer, acceptable to
the Trustee if such opinion is to be delivered to the Trustee; provided,
however, that with respect to REMIC matters, matters relating to the
determination of Eligible Accounts or matters relating to transfers of
Certificates, such counsel shall be Independent.

      Optimal Adjustment Event: With respect to any Class of Class B
Certificates and any Distribution Date, an Optimal Adjustment Event will
occur with respect to such Class if: (i) the Principal Balance of such Class
on the Determination Date succeeding such Distribution Date would have been
reduced to zero (regardless of whether such Principal Balance was reduced to
zero as a result of principal distribution or the allocation of Realized
Losses) and (ii) (a) the Principal Balance of any Class of Class A Non-PO
Certificates would be subject to further reduction as a result of the third
sentence of the definition of Principal Balance or (b) the Principal Balance
of a Class of Class B Certificates with a lower numerical designation would
be reduced with respect to such Distribution Date as a result of the
application of the proviso in the definition of Class B-1 Principal Balance,
Class B-2 Principal Balance, Class B-3 Principal Balance, Class B-4 Principal
Balance or Class B-5 Principal Balance, as applicable.

      Original Aggregate Non-PO Principal Balance: The Aggregate Non-PO
Principal Balance as of the Cut-Off Date, as set forth in Section 11.06.

      Original Class A Percentage: The Class A Percentage as of the Cut-Off
Date as set forth in Section 11.03.

      Original Class B Principal Balance: The sum of the Original Class B-1
Principal Balance, the Original Class B-2 Principal Balance, the Original
Class B-3 Principal Balance, the Original Class B-4 Principal Balance, the
Original Class B-5 Principal Balance and the Original Class B-6 Principal
Balance, as set forth in Section 11.07.

      Original Class B-1 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class B-2
Principal Balance, the Original Class B-3 Principal Balance, the Original
Class B-4 Principal Balance, the Original Class B-5 Principal Balance and the
Original Class B-6 Principal Balance by the Original Aggregate Non-PO
Principal Balance. The Original Class B-1 Fractional Interest is specified in
Section 11.09.

      Original Class B-2 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class B-3
Principal Balance, the Original Class B-4 Principal Balance, the Original
Class B-5 Principal Balance and the Original Class B-6 Principal Balance by
the Original Aggregate Non-PO Principal Balance. The Original Class B-2
Fractional Interest is specified in Section 11.10.

      Original Class B-3 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class B-4
Principal Balance, the Original Class B-5 Principal Balance and the Original
Class B-6 Principal Balance by the Original Aggregate Non-PO Principal
Balance. The Original Class B-3 Fractional Interest is specified in Section
11.11.

      Original Class B-4 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class B-5
Principal Balance and the Original Class B-6 Principal Balance by the
Original Aggregate Non-PO Principal Balance. The Original Class B-4
Fractional Interest is specified in Section 11.12.

      Original Class B-5 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the Original Class B-6 Principal
Balance by the Original Aggregate Non-PO Principal Balance. The Original
Class B-5 Fractional Interest is specified in Section 11.13.

      Original Class B-1 Percentage: The Class B-1 Percentage as of the
Cut-Off Date, as set forth in Section 11.14.

      Original Class B-2 Percentage: The Class B-2 Percentage as of the
Cut-Off Date, as set forth in Section 11.15.

      Original Class B-3 Percentage: The Class B-3 Percentage as of the
Cut-Off Date, as set forth in Section 11.16.

      Original Class B-4 Percentage: The Class B-4 Percentage as of the
Cut-Off Date, as set forth in Section 11.17.

      Original Class B-5 Percentage: The Class B-5 Percentage as of the
Cut-Off Date, as set forth in Section 11.18.

      Original Class B-6 Percentage: The Class B-6 Percentage as of the
Cut-Off Date, as set forth in Section 11.19.

      Original Class B-1 Principal Balance: The Class B-1 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.08.

      Original Class B-2 Principal Balance: The Class B-2 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.08.

      Original Class B-3 Principal Balance: The Class B-3 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.08.

      Original Class B-4 Principal Balance: The Class B-4 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.08.

      Original Class B-5 Principal Balance: The Class B-5 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.08.

      Original Class B-6 Principal Balance: The Class B-6 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.08.

      Original Principal Balance: Any of the Original Principal Balances of
the Classes of Class A Certificates as set forth in Section 11.05; the
Original Class B-1 Principal Balance, Original Class B-2 Principal Balance,
Original Class B-3 Principal Balance, Original Class B-4 Principal Balance,
Original Class B-5 Principal Balance or Original Class B-6 Principal Balance
as set forth in Section 11.08.

      Other Servicer: Any of the Servicers other than Wells Fargo Bank.

      Other Servicer Mortgage Loan: Any of the Mortgage Loans, if any,
identified on the Mortgage Loan Schedule as serviced by an Other Servicer, as
such Mortgage Loan Schedule may be amended from time to time in connection
with a substitution pursuant to Section 2.02 or 2.03, which Mortgage Loan is
serviced under an Other Servicing Agreement.

      Other Servicing Agreements: The Servicing Agreements other than the
Wells Fargo Bank Servicing Agreement.

      Outstanding Certificate: Any Outstanding Exchangeable Certificate or
Outstanding Exchangeable REMIC Certificate.

      Outstanding Exchangeable Certificate: Any Exchangeable Certificate
issued hereunder; provided, however, that upon the exchange of any
Exchangeable Certificate pursuant to Section 5.04 hereof, the Exchangeable
Certificate so exchanged shall be deemed no longer to be an Outstanding
Exchangeable Certificate, and each Exchangeable REMIC Certificate issued in
exchange therefor shall be deemed to be an Outstanding Exchangeable REMIC
Certificate.

      Outstanding Exchangeable REMIC Certificate: Any Exchangeable REMIC
Certificate issued hereunder; provided, however, that upon the exchange of
any Exchangeable REMIC Certificate pursuant to Section 5.04 hereof, the
Exchangeable REMIC Certificate so exchanged shall be deemed no longer to be
an Outstanding Exchangeable REMIC Certificate, and the Exchangeable
Certificate issued in exchange therefor shall be deemed to be an Outstanding
Exchangeable Certificate.

      Outstanding Mortgage Loan: As to any Due Date, a Mortgage Loan
(including an REO Mortgage Loan) which was not the subject of a Full
Unscheduled Principal Receipt prior to such Due Date and which was not
repurchased by the Depositor prior to such Due Date pursuant to Section 2.02,
2.03 or 3.08.

      Owner Mortgage Loan File: A file maintained by the Custodian for each
Mortgage Loan that contains the documents specified in Section 2.01(a) and
any additional documents required to be added to the Owner Mortgage Loan File
pursuant to this Agreement.

      Partial Liquidation Proceeds: Liquidation Proceeds received by a
Servicer prior to the Unscheduled Principal Receipt Period in which the
related Mortgage Loan became a Liquidated Loan.

      Partial Unscheduled Principal Receipt: An Unscheduled Principal Receipt
which is not a Full Unscheduled Principal Receipt.

      Paying Agent: The Person authorized to make distributions to
Certificateholders with respect to the Certificates and to forward to
Certificateholders the periodic and annual statements required by Section
4.04. The Paying Agent may be the Trustee. The initial Paying Agent is
appointed in Section 4.03(b).

      Paying Agent Agreement: As defined in Section 4.03(b).

      Payment Account: The account maintained pursuant to Section 4.03(a).

      Percentage Interest: With respect to a Class A Certificate of a Class,
the undivided percentage interest obtained by dividing the Denomination of
such Certificate by the Original Principal Balance of such Class of Class A
Certificates (or the Maximum Initial Principal Balance in the case of a Class
of Exchangeable REMIC Certificates or Exchangeable Certificates). With
respect to a Class B Certificate of a Class, the undivided percentage
interest obtained by dividing the Denomination of such Certificate by the
Original Principal Balance of such Class of Class B Certificates.
Notwithstanding the foregoing, for purposes of making actual distributions of
principal or interest, allocating losses or allocating Voting Interest among
the Outstanding Exchangeable REMIC Certificates or Outstanding Exchangeable
Certificates of a Class, the Percentage Interest refers to each Outstanding
Certificate's proportionate share of such actual distributions, Realized
Losses or Voting Interests based on the proportion that such Certificate's
Percentage Interest, as defined in the first two sentences bears to the
aggregate Percentage Interest as defined in the first two sentences of all
the Outstanding Exchangeable REMIC Certificates or Outstanding Exchangeable
Certificates of such Class.

      Periodic Advance: The aggregate of the advances required to be made by
a Servicer on any Remittance Date pursuant to its Servicing Agreement or by
the Master Servicer or the Trustee hereunder on any Distribution Date, the
amount of any such advances being equal to the total of all Monthly Payments
(adjusted, in each case (i) in respect of interest, to the applicable
Mortgage Interest Rate less the applicable Servicing Fee Rate in the case of
Periodic Advances made by a Servicer and to the applicable Net Mortgage
Interest Rate in the case of Periodic Advances made by the Master Servicer or
Trustee and (ii) by the amount of any related Debt Service Reductions or
reductions in the amount of interest collectable from the Mortgagor pursuant
to the Servicemembers Civil Relief Act, as it may be amended from time to
time, or similar legislation or regulations then in effect) on the Mortgage
Loans, that (x) were delinquent as of the close of business on the related
Determination Date, (y) were not the subject of a previous Periodic Advance
by such Servicer or of a Periodic Advance by the Master Servicer or the
Trustee, as the case may be and (z) have not been determined by the Master
Servicer, such Servicer or Trustee to be Nonrecoverable Advances. For
purposes of the preceding sentence, the Monthly Payment on each Balloon Loan
with a delinquent Balloon Payment is equal to the assumed monthly payment
that would have been due on the related Due Date based on the original
principal amortization schedule for such Balloon Loan.

      Person: Any individual, corporation, partnership, joint venture,
association, joint-stock company, trust, unincorporated organization or
government or any agency or political subdivision thereof.

      Plan: As defined in Section 5.02(c).

      PMI Advance: As defined in the related Servicing Agreement, if
applicable.

      PO Fraction: With respect to any Discount Mortgage Loan, the difference
between 1.0 and the Non-PO Fraction for such Mortgage Loan; with respect to
any other Mortgage Loan, zero.

      Pool Balance (Non-PO Portion): As of any Distribution Date, the sum of
the amounts for each Mortgage Loan that is an Outstanding Mortgage Loan of
the product of (i) the Non-PO Fraction for such Mortgage Loan and (ii) the
Scheduled Principal Balance of such Mortgage Loan.

      Pool Balance (PO Portion): As of any Distribution Date, the sum of the
amounts for each Mortgage Loan that is an Outstanding Mortgage Loan of the
product of (i) the PO Fraction for such Mortgage Loan and (ii) the Scheduled
Principal Balance of such Mortgage Loan.

      Pool Distribution Amount: As of any Distribution Date, the funds
eligible for distribution to the Class A Certificates and Class B
Certificates on such Distribution Date, which shall be the sum of (i) all
previously undistributed payments or other receipts on account of principal
and interest on or in respect of the Mortgage Loans (including, without
limitation, the proceeds of any repurchase of a Mortgage Loan by the
Depositor and any Substitution Principal Amount) received by the Master
Servicer with respect to the applicable Remittance Date in the month of such
Distribution Date and any Unscheduled Principal Receipts received by the
Master Servicer on or prior to the Business Day preceding such Distribution
Date, (ii) all Periodic Advances made by a Servicer pursuant to the related
Servicing Agreement or Periodic Advances made by the Master Servicer or the
Trustee pursuant to Section 3.03, (iii) any remaining Reimbursement Amount as
provided in Section 4.01(a) and (iv) all other amounts (including any
Insurance Proceeds and Compensating Interest) required to be placed in the
Certificate Account by the Servicers on or before the applicable Remittance
Date or by the Master Servicer or the Trustee on or prior to the Distribution
Date, but excluding the following:

         (a) amounts received as late payments of principal or interest and
   respecting which the Master Servicer or the Trustee has made one or more
   unreimbursed Periodic Advances;

         (b) the portion of Liquidation Proceeds used to reimburse any
   unreimbursed Periodic Advances by the Master Servicer or the Trustee;

         (c) that portion of each payment of interest on a particular
   Mortgage Loan which represents (i) the Fixed Retained Yield, if any, (ii)
   the applicable Servicing Fee and (iii) the Master Servicing Fee;

         (d) all amounts representing scheduled payments of principal and
   interest due after the Due Date occurring in the month in which such
   Distribution Date occurs;

         (e) all Unscheduled Principal Receipts received by the Servicers
   after the Applicable Unscheduled Principal Receipt Period relating to the
   Distribution Date for the applicable type of Unscheduled Principal
   Receipt, and all related payments of interest on such amounts;

         (f) all repurchase proceeds with respect to Mortgage Loans
   repurchased by the Depositor pursuant to Section 2.02, 2.03 or 3.08 on or
   following the Determination Date in the month in which such Distribution
   Date occurs and the Substitution Principal Amounts with respect to any
   Mortgage Loans for which Mortgage Loans were substituted on or following
   the Determination Date in the month in which such Distribution Date occurs;

         (g) that portion of Liquidation Proceeds and REO Proceeds which
   represents any unpaid Servicing Fee or Master Servicing Fee;

         (h) all income from Eligible Investments that is held in the
   Certificate Account for the account of the Master Servicer;

         (i) Liquidation Profits;

         (j) Month End Interest;

         (k) all amounts reimbursable to a Servicer for PMI Advances; and

         (l) all other amounts permitted to be withdrawn from the Certificate
   Account, to the extent not covered by clauses (a) through (k) above, or
   not required to be deposited in the Certificate Account under this
   Agreement.

      Pool Scheduled Principal Balance: As to any Distribution Date, the
aggregate Scheduled Principal Balance of all Mortgage Loans that were
Outstanding Mortgage Loans on the Due Date in the month preceding the month
of such Distribution Date.

      Premium Mortgage Loan: A Mortgage Loan with a Net Mortgage Interest
Rate equal to or greater than 6.000%.

      Prepayment In Full: With respect to any Mortgage Loan, a Mortgagor
payment consisting of a Principal Prepayment in the amount of the outstanding
principal balance of such loan and resulting in the full satisfaction of such
obligation.

      Prepayment Interest Shortfall: On any Distribution Date, the amount of
interest, if any, that would have accrued on any Mortgage Loan which was the
subject of a Prepayment in Full at the Mortgage Interest Rate for such
Mortgage Loan from the date of its Prepayment in Full (but in the case of a
Prepayment in Full where the Applicable Unscheduled Principal Receipt Period
is the Mid-Month Receipt Period, only if the date of the Prepayment in Full
is on or after the Determination Date in the month prior to the month of such
Distribution Date and prior to the first day of the month of such
Distribution Date) through the last day of the month prior to the month of
such Distribution Date.

      Principal Adjustment: In the event that the Class B-1 Optimal Principal
Amount, Class B-2 Optimal Principal Amount, Class B-3 Optimal Principal
Amount, Class B-4 Optimal Principal Amount, Class B-5 Optimal Principal
Amount or Class B-6 Optimal Principal Amount is calculated in accordance with
the proviso in such definition with respect to any Distribution Date, the
Principal Adjustment for such Class of Class B Certificates shall equal the
difference between (i) the amount that would have been distributed to such
Class as principal in accordance with Section 4.01(a) for such Distribution
Date, calculated without regard to such proviso and assuming there are no
Principal Adjustments for such Distribution Date and (ii) the Adjusted
Principal Balance for such Class.

      Principal Balance: As of the first Determination Date and as to any
Class of Class A Certificates (other than any Class of Exchangeable
Certificates), the Original Principal Balance or, in the case of a Class of
Exchangeable REMIC Certificates, the Maximum Initial Principal Balance of
such Class. As of any subsequent Determination Date prior to the
Subordination Depletion Date and as to any Class of Class A Non-PO
Certificates, the Original Principal Balance or, in the case of a Class of
Exchangeable REMIC Certificates, the Maximum Initial Principal Balance of
such Class less the sum of all amounts previously distributed in respect of
such Class on prior Distribution Dates (i) pursuant to Paragraph third clause
(1) of Section 4.01(a) and (ii) as a result of a Principal Adjustment. After
the Subordination Depletion Date, each such Principal Balance of a Class of
Class A Non-PO Certificates will also be reduced (if clause (a) is greater
than clause (b)) or increased (if clause (a) is less than clause (b)) on each
Determination Date by an amount equal to the product of the Class A Loss
Percentage of such Class and the difference, if any, between (a) the Class A
Non-PO Principal Balance as of such Determination Date without regard to this
sentence and (b) the Adjusted Pool Amount (Non-PO Portion) for the preceding
Distribution Date; provided, however, that the amount of any such reduction
for the Class A-2 Certificates will be decreased by the Class A-3 Loss
Allocation Amount. After the Subordination Depletion Date, the Principal
Balance for the Class A-3 Certificates will additionally be reduced by the
Class A-3 Loss Allocation Amount. In addition, any increase allocated to the
Class A-2 Certificates pursuant to the third sentence above will instead
increase the Principal Balance of the Class A-3 Certificates.

      A Class of Exchangeable Certificates has no Principal Balance.

      As of any subsequent Determination Date and as to the Class A-PO
Certificates, the Original Principal Balance of such Class less the sum of
all amounts previously distributed in respect of the Class A-PO Certificates
on prior Distribution Dates pursuant to Paragraph third clause (2) of
Section 4.01(a). The Principal Balance of the Class A-PO Certificates will
also be reduced (if clause (x) is greater than clause (y)) or increased (if
clause (x) is less than clause (y)) on each Determination Date by the
difference, if any, between (x) the Principal Balance of the Class A-PO
Certificates as of such Determination Date without regard to this sentence
and (y) the Adjusted Pool Amount (PO Portion) for the preceding Distribution
Date.

      As to the Class B Certificates, the Class B-1 Principal Balance, Class
B-2 Principal Balance, Class B-3 Principal Balance, Class B-4 Principal
Balance, Class B-5 Principal Balance and Class B-6 Principal Balance,
respectively.

      Notwithstanding the foregoing, no Principal Balance of a Class will be
increased on any Determination Date such that the Principal Balance of such
Class exceeds its Original Principal Balance or Maximum Initial Principal
Balance less all amounts previously distributed in respect of such Class on
prior Distribution Dates pursuant to Paragraph third clause (1) of Section
4.01(a), Paragraph third clause (2) of Section 4.01(a), or Paragraphs
seventh, tenth, thirteenth, sixteenth, nineteenth or twenty-second of Section
4.01(a).

      Principal Prepayment: Any Mortgagor payment on a Mortgage Loan which is
received in advance of its Due Date and is not accompanied by an amount
representing scheduled interest for any period subsequent to the date of
prepayment.

      Prior Month Receipt Period: With respect to each Distribution Date, the
calendar month preceding the month in which such Distribution Date occurs.

      Prohibited Transaction Tax: Any tax imposed under Section 860F of the
Code.

      Prospectus: The prospectus dated December 17, 2007 as supplemented by
the prospectus supplement dated December 17, 2007, relating to the Class A,
Class B-1, Class B-2 and Class B-3 Certificates.

      Prudent Servicing Practices: The standard of care set forth in each
Servicing Agreement.

      Rating Agency: Any nationally recognized statistical credit rating
agency, or its successor, that rated one or more Classes of the Certificates
at the request of the Depositor at the time of the initial issuance of the
Certificates. The Rating Agencies for the Class A-1, Class A-2, Class A-3 and
Class A-PO Certificates are Fitch and Moody's. The Rating Agency for the
Class A-R, Class B-1, Class B-2, Class B-3, Class B-4 and Class B-5
Certificates is Fitch. If any such agency or a successor is no longer in
existence, "Rating Agency" shall be such statistical credit rating agency, or
other comparable Person, designated by the Depositor, notice of which
designation shall be given to the Trustee and the Master Servicer. References
herein to the highest short-term rating category of a Rating Agency shall
mean F-1+ in the case of Fitch, P-1 in the case of Moody's, and in the case
of any other Rating Agency shall mean its equivalent of such ratings.
References herein to the highest long-term rating categories of a Rating
Agency shall mean AAA in the case of Fitch, Aaa in the case of Moody's, and
in the case of any other Rating Agency shall mean its equivalent of such
ratings without any plus or minus.

      Realized Losses: With respect to any Distribution Date, (i) Liquidated
Loan Losses incurred on Liquidated Loans for which the Liquidation Proceeds
were received during the Applicable Unscheduled Principal Receipt Period with
respect to Full Unscheduled Principal Receipts with respect to such
Distribution Date and (ii) Bankruptcy Losses incurred during the period
corresponding to the Applicable Unscheduled Principal Receipt Period with
respect to Full Unscheduled Principal Receipts for such Distribution Date.

      Record Date: The last Business Day of the month preceding the month of
the related Distribution Date.

      Recovery: Any amount received (net of any reimbursable expenses) on a
Mortgage Loan subsequent to such Mortgage Loan being determined to be a
Liquidated Loan.

      Regulation AB: Subpart 229.1100 - Asset Backed Securities (Regulation
AB), 17 C.F.R. ss.ss.229.1100-229.1123, as such may be amended from time to
time, and subject to such clarification and interpretation as have been publicly
provided by the Commission in the adopting release (Asset-Backed Securities,
Securities Act Release No. 33-8518, 70 Fed. Reg. 1,506 (Jan. 7, 2005)) or by the
staff of the Commission, or as may be provided by the Commission or its staff
from time to time.

      Reimbursement Amount: As defined in Section 2.03(c).

      Related Exchangeable Certificates: As to any Class or Classes of
Exchangeable REMIC Certificates, the Class or Classes of Exchangeable
Certificates included in the same Combination Group.

      Related Exchangeable REMIC Certificates: As to any Class or Classes of
Exchangeable Certificates, the Class or Classes of Exchangeable REMIC
Certificates included in the same Combination Group.

      Relevant Servicing Criteria: The Servicing Criteria applicable to the
Master Servicer, the Trustee, the Custodian or the Servicers, as set forth on
Exhibit R attached hereto and the Servicing Criteria applicable to any
Special Servicer as set forth in the applicable Special Servicing Agreement.
For clarification purposes, multiple parties can have responsibility for the
same Relevant Servicing Criteria. With respect to a Servicing Function
Participant engaged by the Master Servicer, the Trustee, the Custodian, the
Special Servicer (if applicable) or a Servicer, the term "Relevant Servicing
Criteria" refers to the portion of the Relevant Servicing Criteria applicable
to the party engaging such Servicing Function Participant insofar as the
functions required to be performed by such party are to be performed by the
Servicing Function Participant.

      Relief Act Shortfall: Any interest shortfalls arising as a result of
the reduction in the amount of monthly interest payments on any Mortgage
Loans as a result of the application of the Servicemembers Civil Relief Act,
as it may be amended from time to time, or comparable state legislation. Any
Relief Act Shortfall will be allocated to (a) the Class A Non-PO Certificates
according to the percentage obtained by dividing the Class A Non-PO Principal
Balance by the Aggregate Non-PO Principal Balance and (b) the Class B
Certificates according to the percentage obtained by dividing the Class B
Principal Balance by the Aggregate Non-PO Principal Balance.

      REMIC: A "real estate mortgage investment conduit" as defined in Code
Section 860D.

      REMIC Provisions: Provisions of the federal income tax law relating to
REMICs, which appear at Sections 860A through 860G of Part IV of Subchapter M
of Chapter 1 of Subtitle A of the Code, and related provisions, and U.S.
Department of the Treasury temporary, proposed or final regulations
promulgated thereunder, as the foregoing are in effect (or with respect to
proposed regulations, are proposed to be in effect) from time to time.

      Remittance Date: As defined in each of the Servicing Agreements.

      REO Mortgage Loan: Any Mortgage Loan which is not a Liquidated Loan and
as to which the indebtedness evidenced by the related Mortgage Note is
discharged and the related Mortgaged Property is held as part of the Trust
Estate.

      REO Proceeds: Proceeds received in respect of any REO Mortgage Loan
(including, without limitation, proceeds from the rental of the related
Mortgaged Property).

      Reportable Event: As defined in Section 3.12(c).

      Repurchase Price: With respect to any Mortgage Loan repurchased
pursuant to Section 2.02, 2.03 or 3.08 hereof, the sum of (a) 100% of the
unpaid principal balance of such Mortgage Loan plus (b) accrued interest at
the Mortgage Interest Rate less any Fixed Retained Yield, through the last
day of the month in which such repurchase takes place.

      Request for Release: A request for release (which may be in electronic
form) in substantially the form attached as Exhibit G hereto.

      Residual Certificate: The Class A-R Certificate.

      Responsible Officer: When used with respect to the Trustee, the Master
Servicer, the Custodian, the Paying Agent or the Authenticating Agent, any
officer of the Corporate Trust Department of the Trustee, the Master
Servicer, the Custodian, the Paying Agent or the Authenticating Agent having
direct responsibility for the administration of this Agreement, including any
Senior Vice President, any Vice President, any Assistant Vice President, any
Assistant Secretary, any Trust Officer or Assistant Trust Officer, or any
other employee of the Trustee, the Master Servicer, the Custodian, the Paying
Agent or the Authenticating Agent customarily performing functions similar to
those performed by any of the above-designated officers. When used with
respect to a Servicer, a Servicing Officer.

      Retained Mortgage Loan File: A file maintained by Wells Fargo Bank
prior to any Document Transfer Date for each Mortgage Loan that contains the
documents specified in Section 2.01(b) and any additional documents required
to be added to the Retained Mortgage Loan File pursuant to this Agreement.

      Rule 144A: Rule 144A promulgated under the 1933 Act.

      S&P: Standard & Poor's, a division of The McGraw-Hill Companies, Inc.,
or its successor in interest.

      Sarbanes-Oxley Certification: As defined in Section 3.12(b).

      Scheduled Principal Balance: As to any Mortgage Loan and Distribution
Date, the principal balance of such Mortgage Loan as of the Due Date in the
month preceding the month of such Distribution Date as specified in the
amortization schedule at the time relating thereto (before any adjustment to
such amortization schedule by reason of any bankruptcy (other than Deficient
Valuations) or similar proceeding or any moratorium or similar waiver or
grace period or any Capitalized Advance Amounts) after giving effect to (A)
Unscheduled Principal Receipts received or applied by the applicable Servicer
during the related Unscheduled Principal Receipt Period for each applicable
type of Unscheduled Principal Receipt related to the Distribution Date
occurring in the month preceding such Distribution Date, (B) Deficient
Valuations incurred prior to such Due Date and (C) the payment of principal
due on such Due Date and irrespective of any delinquency in payment by the
related Mortgagor. Accordingly, the Scheduled Principal Balance of a Mortgage
Loan which becomes a Liquidated Loan at any time through the last day of such
related Unscheduled Principal Receipt Period shall be zero.

      Servicer Modification: A permanent modification to the terms of a
Mortgage Loan, in accordance with the terms of Section 3.08, as to which the
Mortgagor is in default or as to which, in the judgment of the Servicer,
default is reasonably foreseeable.

      Servicer Mortgage Loan File: As defined in each of the Servicing
Agreements.

      Servicers: Each of Wells Fargo Bank and Colonial Savings, F.A., as a
Servicer under the related Servicing Agreement. Initially the servicing
functions performed by Wells Fargo Bank shall be performed by the Wells Fargo
Home Mortgage division of Wells Fargo Bank.

      Servicing Agreements: Each of the Servicing Agreements executed with
respect to a portion of the Mortgage Loans by one of the Servicers, which
agreements are listed on Exhibit L.

      Servicing Criteria: The "servicing criteria" set forth in Item 1122(d)
of Regulation AB, as such may be amended from time to time.

      Servicing Fee: With respect to any Servicer, as defined in its
Servicing Agreement.

      Servicing Fee Rate: With respect to a Mortgage Loan, as set forth in
Section 11.23.

      Servicing Function Participant: Any Subservicer, Subcontractor or any
other Person, other than the Master Servicer, the Trustee, the Custodian, the
Special Servicer (if applicable) and the Servicers, that is performing
activities addressed by the Servicing Criteria.

      Servicing Officer: Any officer of a Servicer involved in, or
responsible for, the administration and servicing of the Mortgage Loans.

      Similar Law: As defined in Section 5.02(c).

      Special Servicer: As defined in Section 3.08.

      Special Servicing Agreement: As defined in Section 3.08.

      Single Certificate: A Certificate of any Class that evidences the
smallest permissible Denomination for such Class, as set forth in Section
11.22.

      Startup Day: As defined in Section 2.05.

      Subcontractor: Any vendor, subcontractor or other Person that is not
responsible for the overall servicing of Mortgage Loans but performs one or
more discrete functions identified in Item 1122(d) of Regulation AB with
respect to Mortgage Loans under the direction or authority of any Servicer
(or a Subservicer of any Servicer), the Master Servicer, the Trustee or the
Custodian.

      Subordinated Percentage: As to any Distribution Date, the percentage
which is the difference between 100% and the Class A Percentage for such date.

      Subordinated Prepayment Percentage: As to any Distribution Date, the
percentage which is the difference between 100% and the Class A Prepayment
Percentage for such date.

      Subordination Depletion Date: The Distribution Date preceding the first
Distribution Date on which the Class A Percentage (determined pursuant to
clause (ii) of the definition thereof) equals or exceeds 100%.

      Subordination Depletion Date Interest Shortfall: With respect to any
Distribution Date that occurs on or after the Subordination Depletion Date
with respect to any Unscheduled Principal Receipt (other than a Prepayment in
Full or Curtailment):

      (A)   in the case where the Applicable Unscheduled Principal Receipt
            Period is the Mid-Month Receipt Period and such Unscheduled
            Principal Receipt is received by the applicable Servicer on or after
            the Determination Date in the month preceding the month of such
            Distribution Date but prior to the first day of the month of such
            Distribution Date, the amount of interest that would have accrued at
            the Mortgage Interest Rate on the amount of such Unscheduled
            Principal Receipt from the day of its receipt or, if earlier, its
            application by such Servicer through the last day of the month
            preceding the month of such Distribution Date; and

      (B)   in the case where the Applicable Unscheduled Principal Receipt
            Period is the Prior Month Receipt Period and such Unscheduled
            Principal Receipt is received by the applicable Servicer during the
            month preceding the month of such Distribution Date, the amount of
            interest that would have accrued at the Mortgage Interest Rate on
            the amount of such Unscheduled Principal Receipt from the day of its
            receipt or, if earlier, its application by such Servicer through the
            last day of the month in which such Unscheduled Principal Receipt is
            received.

      Subservicer: Any Person that (i) services Mortgage Loans on behalf of
any Servicer, and (ii) is responsible for the performance (whether directly
or through Subservicers or Subcontractors) of a substantial portion of the
material servicing functions required to be performed under this Agreement,
any related Servicing Agreement or any sub-servicing agreement that are
identified in Item 1122(d) of Regulation AB.

      Subsidy Account: If the Trust Estate contains any Subsidy Loans, the
deposit account or accounts created and maintained by the applicable Servicer
for deposit of Subsidy Funds and amounts payable under interest subsidy
agreements relating to mortgage loans other than the Mortgage Loans.

      Subsidy Funds: If the Trust Estate contains any Subsidy Loans, funds
contributed by the employer of a Mortgagor in order to reduce the payments
required from the Mortgagor for a specified period in specified amounts.

      Subsidy Loan: Any Mortgage Loan subject to a temporary interest subsidy
agreement pursuant to which the monthly interest payments made by the related
Mortgagor will be less than the scheduled monthly interest payments on such
Mortgage Loan, with the resulting difference in interest payments being
provided by the employer of the Mortgagor.

      Substitute Mortgage Loan: As defined in Section 2.02.

      Substitution Principal Amount: With respect to any Mortgage Loan
substituted in accordance with Section 2.02 or pursuant to Section 2.03, the
excess of (x) the unpaid principal balance of the Mortgage Loan which is
substituted for over (y) the unpaid principal balance of the Substitute
Mortgage Loan, each balance being determined as of the date of substitution.

      Trust: The New York common law trust created by this Agreement which
shall be entitled "Wells Fargo Mortgage Backed Securities 2007-17 Trust."

      Trust Estate: The corpus of the Trust, consisting of the Mortgage Loans
(other than any Fixed Retained Yield), such amounts as may be held from time
to time in the Certificate Account (other than any Fixed Retained Yield), the
rights of the Trustee to receive the proceeds of all insurance policies and
performance bonds, if any, required to be maintained hereunder or under the
related Servicing Agreement, property which secured a Mortgage Loan and which
has been acquired by foreclosure or deed in lieu of foreclosure and all other
property and rights described in the first paragraph of Section 2.01(a).

      Trustee: HSBC Bank USA, National Association, a national banking
association, or any successor trustee appointed as herein provided.

      Trustee Errors and Omissions Policy: An insurance policy covering
losses caused by errors or omissions of the Trustee and its personnel.

      Type 1 Mortgage Loan: The Mortgage Loans, if any, identified as such in
the Mortgage Loan Schedule as such Mortgage Loan Schedule may be amended from
time to time in connection with a substitution pursuant to Section 2.02 or
2.03, serviced under the Wells Fargo Bank Servicing Agreement and having a
Mid-Month Receipt Period with respect to all types of Unscheduled Principal
Receipts.

      Type 2 Mortgage Loan: The Mortgage Loans, if any, identified as such in
the Mortgage Loan Schedule as such Mortgage Loan Schedule may be amended from
time to time in connection with a substitution pursuant to Section 2.02 or
2.03, serviced under the Wells Fargo Bank Servicing Agreement and having a
Prior Month Receipt Period with respect to all types of Unscheduled Principal
Receipts.

      Underwriting Guidelines: The underwriting standards for the Mortgage
Loans as described in the Prospectus.

      Unpaid Interest Shortfalls: Each of the Class A Unpaid Interest
Shortfalls, the Class B-1 Unpaid Interest Shortfall, the Class B-2 Unpaid
Interest Shortfall, the Class B-3 Unpaid Interest Shortfall, the Class B-4
Unpaid Interest Shortfall, the Class B-5 Unpaid Interest Shortfall and the
Class B-6 Unpaid Interest Shortfall.

      Unscheduled Principal Receipt: Any Principal Prepayment or other
recovery of principal on a Mortgage Loan, including, without limitation, the
principal portion of Net Liquidation Proceeds, the principal portion of Net
REO Proceeds, Recoveries and proceeds received from any condemnation award or
proceeds in lieu of condemnation other than that portion of such proceeds
released to the Mortgagor in accordance with the terms of the Mortgage or
Prudent Servicing Practices, but excluding any Liquidation Profits and
proceeds of a repurchase of a Mortgage Loan by the Depositor and any
Substitution Principal Amounts.

      Unscheduled Principal Receipt Period: Either a Mid-Month Receipt Period
or a Prior Month Receipt Period.

      Unverified Information: Information regarding the Mortgagor's income,
source of income, or assets that is stated on the loan application for a
Mortgage Loan by the Mortgagor but not verified in the origination process
pursuant to the applicable Underwriting Guidelines at the time of origination.

      U.S. Person: As defined in Section 4.01(f).

      Voting Interest: With respect to any provisions hereof providing for
the action, consent or approval of the Holders of all Certificates evidencing
specified Voting Interests in the Trust Estate, each Class of Certificates
(other than the Exchangeable Certificates) will be entitled to a pro rata
portion of the aggregate Voting Interest represented by all Certificates
(other than the Exchangeable Certificates) equal to the ratio obtained by
dividing the Principal Balance of such Class by the Aggregate Principal
Balance. With respect to any provisions hereof providing for action, consent
or approval of each Class of Certificates or specified Classes of
Certificates (other than the Exchangeable Certificates), each
Certificateholder of a Class will have a Voting Interest equal to the product
of the Voting Interest to which such Class is collectively entitled and the
Percentage Interest in such Class represented by such Holder's Certificates.
As to a Class of Exchangeable Certificates, in the event that all or a
portion of the Class or Classes of Exchangeable REMIC Certificates in an
Exchangeable REMIC Combination are exchanged for a proportionate portion of
the related Exchangeable Combination, each Class or Classes of Exchangeable
Certificates included in such Exchangeable Combination will be entitled to
its proportionate share of the Voting Interests allocated to such Class or
Classes of Exchangeable REMIC Certificates in the related Exchangeable REMIC
Combination.

      Wells Fargo Bank: Wells Fargo Bank, N.A., or its successor in interest.

      Wells Fargo Bank Correspondents: The entities identified on a list
provided by Wells Fargo Bank to the Master Servicer, from which Wells Fargo
Bank purchased the Mortgage Loans.

      Wells Fargo Bank Servicing Agreement: The Servicing Agreement providing
for the servicing of those Mortgage Loans that are initially serviced by
Wells Fargo Bank.

      WHFIT: A "Widely Held Fixed Investment Trust" as that term is defined
in Treasury Regulations section 1.671-5(b)(22) or successor provisions.

      WHFIT Regulations: Treasury Regulations section 1.671-5, as amended.

      WHMT: A "Widely Held Mortgage Trust" as that term is defined in
Treasury Regulations section 1.671-5(b)(23) or successor provisions.

      Section 1.02 Acts of Holders.

      (a) Any request, demand, authorization, direction, notice, consent,
waiver or other action provided by this Agreement to be given or taken by
Holders may be embodied in and evidenced by one or more instruments of
substantially similar tenor signed by such Holders in person or by an agent
duly appointed in writing. Except as herein otherwise expressly provided,
such action shall become effective when such instrument or instruments are
delivered to the Trustee. Proof of execution of any such instrument or of a
writing appointing any such agent shall be sufficient for any purpose of this
Agreement and conclusive in favor of the Trustee, if made in the manner
provided in this Section 1.02. The Trustee shall promptly notify the Master
Servicer in writing of the receipt of any such instrument or writing.

      (b) The fact and date of the execution by any Person of any such
instrument or writing may be proved by the affidavit of a witness of such
execution or by a certificate of a notary public or other officer authorized
by law to take acknowledgments of deeds, certifying that the individual
signing such instrument or writing acknowledged to him the execution thereof.
When such execution is by a signer acting in a capacity other than his or her
individual capacity, such certificate or affidavit shall also constitute
sufficient proof of his or her authority. The fact and date of the execution
of any such instrument or writing, or the authority of the individual
executing the same, may also be proved in any other manner which the Trustee
deems sufficient.

      (c) The ownership of Certificates (whether or not such Certificates
shall be overdue and notwithstanding any notation of ownership or other
writing thereon made by anyone other than the Trustee and the Authenticating
Agent) shall be proved by the Certificate Register, and none of the Trustee,
the Depositor or the Master Servicer shall be affected by any notice to the
contrary.

      (d) Any request, demand, authorization, direction, notice, consent,
waiver or other action of the Holder of any Certificate shall bind every
future Holder of the same Certificate and the Holder of every Certificate
issued upon the registration of transfer thereof or in exchange therefor or
in lieu thereof in respect of anything done, omitted or suffered to be done
by the Trustee, the Depositor or the Master Servicer in reliance thereon,
whether or not notation of such action is made upon such Certificate.

      Section 1.03 Effect of Headings and Table of Contents.

      The Article and Section headings in this Agreement and the Table of
Contents are for convenience of reference only and shall not affect the
interpretation or construction of this Agreement.

      Section 1.04 Benefits of Agreement.

      Nothing in this Agreement or in the Certificates, express or implied,
shall give to any Person, other than the parties to this Agreement and their
successors hereunder and the Holders of the Certificates any benefit or any
legal or equitable right, power, remedy or claim under this Agreement.

                                   ARTICLE II

                          CONVEYANCE OF MORTGAGE LOANS;
                      ORIGINAL ISSUANCE OF THE CERTIFICATES

      Section 2.01 Conveyance of Mortgage Loans.

      (a) The Depositor, concurrently with the execution and delivery hereof,
does hereby assign to the Trustee, without recourse all the right, title and
interest of the Depositor in and to (a) the Trust Estate, including all
interest (other than the portion, if any, representing the Fixed Retained
Yield) and principal received by the Depositor on or with respect to the
Mortgage Loans after the Cut-Off Date (and including scheduled payments of
principal and interest due after the Cut-Off Date but received by the
Depositor on or before the Cut-Off Date and Unscheduled Principal Receipts
received or applied on the Cut-Off Date, but not including payments of
principal and interest due on the Mortgage Loans on or before the Cut-Off
Date), (b) the Insurance Policies, (c) the obligations of the Servicers under
the Servicing Agreements with respect to the Mortgage Loans, (d) the right to
receive amounts, if any, payable on behalf of any Mortgagor from the Subsidy
Account relating to any Subsidy Loan and (e) proceeds of all the foregoing.
It is agreed and understood by the Depositor and the Trustee that it is not
intended that any mortgage loan be included in the Trust Estate that is a
"High-Cost Home Loan" as defined in any of (i) the New Jersey Home Ownership
Act effective November 27, 2003, (ii) the New Mexico Home Loan Protection Act
effective January 1, 2004, (iii) the Massachusetts Predatory Home Loan
Practices Act effective November 7, 2004 or (iv) the Indiana Home Loan
Practices Act, effective January 1, 2005.

      In connection with such assignment, the Depositor shall, with respect
to each Mortgage Loan, deliver, or cause to be delivered, to the Custodian,
on or before the Closing Date the following documents or instruments with
respect to each Mortgage Loan.

      (i) The original Mortgage Note either (A) endorsed in blank or (B)
   endorsed as provided in Section 2.01(d), with all prior and intervening
   endorsements as may be necessary to show a complete chain of endorsements
   or with respect to any Mortgage Loan as to which the original Mortgage
   Note has been permanently lost or destroyed and has not been replaced, a
   lost note affidavit with a copy of the Mortgage Note and, in the case of
   any Mortgage Loan originated in the State of New York documented by a
   NYCEMA, the NYCEMA, the new Mortgage Note, if applicable, the consolidated
   Mortgage Note and the consolidated Mortgage;

      (ii) A recorded original assignment of the related Mortgage from Wells
   Fargo Bank assigning the related Mortgage to the Trustee (which may be
   assigned in blank), certified by the recording office, or, if such
   assignment is in the process of being recorded, a copy of the related
   Mortgage transmitted for recordation certified by an officer of Wells
   Fargo Bank or applicable Wells Fargo Bank Correspondent to be a true and
   correct copy of such assignment submitted for recordation; provided,
   however, if recordation is not required as described below, an assignment
   in recordable form (which may be assigned in blank) with respect to the
   related Mortgage;

      (iii) The original of each assumption agreement, modification, written
   assurance or substitution agreement pertaining to such Mortgage Note, if
   any; and

      (iv) For each Mortgage Loan secured by Co-op Shares, the originals of
   the following documents or instruments:

            (a)   The loan security agreement;

            (b)   The stock certificate;

            (c)   The stock power, executed in blank;

            (d)   The executed proprietary lease;

            (e)   The executed recognition agreement;

            (f)   The executed UCC-1 financing statement with evidence of
                  recording thereon; and

            (g)   The executed UCC-3 financing statements or other appropriate
                  UCC financing statements required by state law, evidencing a
                  complete and unbroken chain from the mortgagee to the Trustee
                  with evidence of recording thereon (or in a form suitable for
                  recordation).

      (b) The Master Servicer shall promptly notify the Depositor, the
Trustee and the Custodian of the occurrence of any Document Transfer Event of
which the Master Servicer had knowledge. Following the receipt of such
notice, the Depositor shall, with respect to each Mortgage Loan, deliver, or
cause to be delivered, to the Custodian, no later than the Document Transfer
Date, copies (which may be in electronic form mutually agreed upon by the
Depositor and the Custodian) of the following additional documents or
instruments with respect to each Mortgage Loan; provided, however, that
originals of such documents or instruments shall be delivered to the
Custodian if originals are required under the law in which the related
Mortgaged Property is located in order to exercise all remedies available to
the Trust under applicable law following default by the related Mortgagor:

      (i) The original recorded Mortgage with evidence of recordation noted
   thereon or attached thereto, together with any addenda or riders thereto,
   or a copy of such recorded Mortgage with such evidence of recordation
   certified to be true and correct by the appropriate governmental recording
   office; or a copy of such recorded Mortgage with such evidence of
   recordation, or if the original Mortgage has been submitted for
   recordation but has not been returned from the applicable public recording
   office, a copy of the Mortgage certified by an officer of Wells Fargo Bank
   or the applicable Wells Fargo Bank Correspondent to be a true and correct
   copy of the original Mortgage submitted for recordation;

      (ii) The original of each assumption agreement, modification, written
   assurance or substitution agreement pertaining to such Mortgage, if any,
   or, if such document is in the process of being recorded, a copy of such
   document, certified by an officer of Wells Fargo Bank or the applicable
   Wells Fargo Bank Correspondent of such Mortgage Loan or by the applicable
   title insurance company, closing agent, settlement agent, escrow agent or
   closing attorney to be a true and correct copy of such document
   transmitted for recordation, if any;

      (iii) For each MERS Mortgage Loan that is not a MOM Mortgage Loan, the
   original assignment showing MERS as the assignee of the Mortgage, with
   evidence of recording thereon or copies thereof certified by an officer of
   Wells Fargo Bank or the applicable Wells Fargo Bank Correspondent to have
   been submitted for recordation;

      (iv) Each original recorded intervening assignment of the Mortgage as
   may be necessary to show a complete chain of title from the Mortgage Loan
   originator to Wells Fargo Bank or Wells Fargo Home Mortgage, Inc., with
   evidence of recordation noted thereon or attached thereto, or a copy of
   such assignment with such evidence of recordation to be true and correct
   by the appropriate governmental recording office, or, if any such
   assignment has been submitted for recordation but has not been returned
   from the applicable public recording office or is not otherwise available,
   a copy of such assignment certified by an officer of Wells Fargo Bank or
   the applicable Wells Fargo Bank Correspondent to be a true and correct
   copy of the recorded assignment submitted for recordation; and

      (v) The original policy of the title insurance or certificate of title
   insurance or a written commitment to issue such a title insurance policy
   or certificate of title insurance, or a copy of such title insurance
   certified as true and correct by the applicable insurer or any attorney's
   certificate of title with an Officer's Certificate of Wells Fargo Bank or
   the applicable Wells Fargo Bank Correspondent that such attorney's
   certificate of title is customarily used in lieu of a title insurance
   policy in the jurisdiction in which the related mortgage property is
   located.

      (c) If any assignment of a Mortgage to the Trustee is in the process of
being recorded on the Closing Date, the Depositor shall use its best efforts
to cause each such original recorded document or certified copy thereof to be
delivered to the Custodian promptly following its recordation, but in no
event later than one (1) year following the Closing Date. If any Mortgage has
been recorded in the name of MERS or its designee, no assignment of Mortgage
in favor of the Trustee will be required to be prepared or delivered and
instead, the Master Servicer shall enforce any obligation of the Servicers
under the Servicing Agreements to take all actions as are necessary to cause
the Trust Estate to be shown as the owner of the related Mortgage Loan on the
records of MERS for the purpose of the system of recording transfers of
beneficial ownership of mortgages maintained by MERS. The Depositor shall
also cause to be delivered to the Custodian any other original mortgage loan
document included in the Owner Mortgage Loan File if a copy thereof has been
delivered. The Depositor shall pay from its own funds, without any right of
reimbursement therefor, the amount of any costs, liabilities and expenses
incurred by the Trust Estate by reason of the failure of the Depositor to
cause to be delivered to the Custodian within one (1) year following the
Closing Date any assignment of a Mortgage (except with respect to any
Mortgage recorded in the name of MERS) not delivered to the Custodian on the
Closing Date.

      In lieu of recording an assignment of any Mortgage, the Depositor may,
deliver or cause to be delivered to the Custodian the assignment of the
Mortgage Loan to the Trustee in a form suitable for recordation, if (i) with
respect to a particular state the Trustee has received an Opinion of Counsel
acceptable to it that such recording is not required to make the assignment
effective against the parties to the Mortgage or subsequent purchasers or
encumbrances of the Mortgaged Property or (ii) the Depositor has been advised
by each Rating Agency that non-recordation in a state will not result in a
reduction of the rating assigned by that Rating Agency at the time of initial
issuance of the Certificates. Set forth on Exhibit K attached hereto is a
list of all states where recordation is required by each Rating Agency to
obtain the initial ratings of the Certificates. The Custodian may rely and
shall be protected in relying upon the information contained in such Exhibit
K. In the event that the Custodian receives notice that recording is required
to protect the right, title and interest of the Trustee in and to any such
Mortgage Loan for which recordation of an assignment has not previously been
required, the Custodian shall promptly notify the Trustee and the Custodian
shall, within five Business Days (or such other reasonable period of time
mutually agreed upon by the Custodian and the Trustee) of its receipt of such
notice, deliver each previously unrecorded assignment to the related Servicer
for recordation.

      (d) Except for Mortgage Notes endorsed in blank, endorsements shall
comply with the following format:

                                WITHOUT RECOURSE
                              PAY TO THE ORDER OF:

                     HSBC BANK USA, NATIONAL ASSOCIATION, AS
                     TRUSTEE under the pooling and servicing
                          agreement dated as of [date].
                         and its successors and assigns,

          [Wells Fargo Bank, N.A.] or [Wells Fargo Home Mortgage, Inc.]
                             [Signature of Officer]
                           [Officer's Name and Title]

      Except where assignments in blank are authorized or in the case of any
Mortgage registered in the name of MERS, assignments of any Mortgage shall
comply with the following:

                     HSBC BANK USA, NATIONAL ASSOCIATION, AS
                                     TRUSTEE
                         and its successors and assigns

      (e) Concurrently with the execution and delivery of this Agreement, the
Depositor shall deliver the Mortgage Loan Schedule to the Trustee, the Master
Servicer and the Custodian. The Depositor and the Master Servicer shall
provide a copy of the Mortgage Loan Schedule to any Certificateholders upon
written request made to it at the addresses set forth on Exhibit F, as the
same may be amended from time to time by written notice from such party to
the other parties hereto.

      Section 2.02 Acceptance by Custodian.

      Subject to the provisions of the following paragraph, pursuant to the
Custodial Agreement, the Custodian, on behalf of the Trustee, will declare
that it holds and will hold the documents delivered to it pursuant to Section
2.01(a) above and the other documents constituting a part of the Owner
Mortgage Loan Files or Retained Mortgage Loan Files (after the occurrence of
a Document Transfer Event) delivered to it in trust, upon the trusts herein
set forth, for the use and benefit of all present and future
Certificateholders. Upon execution of this Agreement, the Custodian will
deliver to the Depositor and the Trustee an initial certification in the form
of Exhibit N hereto, to the effect that, except as may be specified in a list
of exceptions attached thereto, it has received the original Mortgage Notes
relating to each Mortgage Loan on the Mortgage Loan Schedule.

      The Custodian will review each Owner Mortgage Loan File within 45 days
after execution of this Agreement. The Custodian will deliver no later than
30 days after completion of such review to the Depositor and the Trustee a
final certification in the form of Exhibit O hereto to the effect that,
except as may be specified in a list of exceptions attached thereto, all
required documents set forth in Section 2.01(a) have been executed and
received and appear regular on their face, and that such documents relate to
the Mortgage Loans identified in the Mortgage Loan Schedule based on a
comparison of the Mortgage Loan identifying number, Mortgagor name and street
address, and in so doing the Custodian may rely on the purported due
execution and genuineness of any such document and on the purported
genuineness of any signature thereon.

      If there are exceptions attached to the final certification, the
Depositor shall have a period of 60 days after the date of receipt of the
final certification within which to correct or cure any such defects. The
Depositor hereby covenants and agrees that, if any material defect is not so
corrected or cured, the Depositor will, not later than 60 days after receipt
of the final certification referred to above respecting such defects, either
(i) repurchase the related Mortgage Loan or any property acquired in respect
thereof from the Trust Estate at a price equal to the Repurchase Price or
(ii) if within two years of the Startup Day, or such other period permitted
by the REMIC Provisions, substitute for any Mortgage Loan to which such
material defect relates, a new mortgage loan (a "Substitute Mortgage Loan")
having such characteristics so that the representations and warranties of the
Depositor set forth in Section 2.03(b) hereof (other than Section 2.03(b)(i))
would not have been incorrect had such Substitute Mortgage Loan originally
been a Mortgage Loan. In no event shall any Substitute Mortgage Loan have an
unpaid principal balance, as of the date of substitution, greater than the
Scheduled Principal Balance (reduced by the scheduled payment of principal
due on the Due Date in the month of substitution) of the Mortgage Loan for
which it is substituted. In addition, such Substitute Mortgage Loan shall
have a Loan-to-Value Ratio less than or equal to and a Net Mortgage Interest
Rate equal to that of the Mortgage Loan for which it is substituted.

      The Depositor shall determine the Repurchase Price or the eligibility
of any Substitute Mortgage Loan and the Trustee shall be protected in relying
on such determination.

      In the case of a repurchased Mortgage Loan or property, the Repurchase
Price shall be remitted by the Depositor to the Master Servicer for deposit
into the Certificate Account maintained by the Master Servicer pursuant to
Section 3.01. In the case of a Substitute Mortgage Loan, the Owner Mortgage
Loan File (and Retained Mortgage Loan File, if required pursuant to Section
2.01(b) hereof) relating thereto shall be delivered to the Custodian and the
Substitution Principal Amount (if any), together with (i) interest on such
Substitution Principal Amount at the applicable Net Mortgage Interest Rate to
the following Due Date of such Mortgage Loan which is being substituted for
and (ii) an amount equal to the aggregate amount of unreimbursed Periodic
Advances in respect of interest previously made by the applicable Servicer,
the Master Servicer or the Trustee with respect to such Mortgage Loan, shall
be remitted by the Depositor to the Master Servicer for deposit into the
Certificate Account. The Monthly Payment on the Substitute Mortgage Loan for
the Due Date in the month of substitution shall not be part of the Trust
Estate. Upon receipt by the Custodian of a Request for Release signed by an
officer of the Depositor, the Custodian shall release to the Depositor the
Owner Mortgage Loan File (and Retained Mortgage Loan File, if applicable) of
the Mortgage Loan being removed. The Trustee shall execute and deliver such
instrument of transfer or assignment (or, in the case of a Mortgage Loan
registered in the name of MERS or its designee, the Master Servicer shall
enforce the obligation of the applicable Servicer under the related Servicing
Agreement to take all necessary action to reflect such assignment on the
records of MERS), in each case without recourse, as shall be necessary to
vest in the Depositor legal and beneficial ownership of such substituted or
repurchased Mortgage Loan or property. It is understood and agreed that the
obligation of the Depositor to substitute a new Mortgage Loan for or
repurchase any Mortgage Loan or property as to which such a material defect
in a constituent document exists shall constitute the sole remedy respecting
such defect available to the Certificateholders or the Trustee on behalf of
the Certificateholders. The failure of the Custodian to give the final
certification or the Trustee to give any notice within the required time
periods shall not affect or relieve the Depositor's obligation to repurchase
any Mortgage Loan pursuant to this Section 2.02.

      The Trustee shall be responsible for enforcing the Depositor's
obligations under this Section 2.02. If the Trustee receives written notice
from the Custodian or the Master Servicer that the defect is not cured by the
Depositor within 60 days after the Trustee's notice, the Trustee shall
enforce the Depositor's obligation to repurchase such Mortgage Loan or
substitute for such Mortgage Loan in accordance with the provisions of this
Section 2.02. In connection with any substitution permitted by this Section
2.02, the Master Servicer shall verify that the unpaid principal balance and
the Loan-to-Value Ratio of the Substitute Mortgage Loan satisfy the
requirements of this Section 2.02.

      Section 2.03 Representations and Warranties of the Master Servicer and
the Depositor.

      (a) The Master Servicer hereby represents and warrants to the Trustee
for the benefit of the Certificateholders that, as of the date of execution
of this Agreement:

      (i) The Master Servicer is a national banking association duly
   chartered and validly existing in good standing under the laws of the
   United States;

      (ii) The execution and delivery of this Agreement by the Master
   Servicer and its performance and compliance with the terms of this
   Agreement will not violate the Master Servicer's corporate charter or
   by-laws or constitute a default (or an event which, with notice or lapse
   of time, or both, would constitute a default) under, or result in the
   breach of, any material contract, agreement or other instrument to which
   the Master Servicer is a party or which may be applicable to the Master
   Servicer or any of its assets;

      (iii) This Agreement, assuming due authorization, execution and
   delivery by the Trustee and the Depositor, constitutes a valid, legal and
   binding obligation of the Master Servicer, enforceable against it in
   accordance with the terms hereof subject to applicable bankruptcy,
   insolvency, reorganization, moratorium and other laws affecting the
   enforcement of creditors' rights generally and to general principles of
   equity, regardless of whether such enforcement is considered in a
   proceeding in equity or at law;

      (iv) The Master Servicer is not in default with respect to any order or
   decree of any court or any order, regulation or demand of any federal,
   state, municipal or governmental agency, which default might have
   consequences that would materially and adversely affect the condition
   (financial or other) or operations of the Master Servicer or its
   properties or might have consequences that would materially affect its
   performance hereunder;

      (v) Except as otherwise disclosed in the Prospectus, no legal or
   governmental proceedings are pending (or known to be contemplated) against
   the Master Servicer that would be material to Certificateholders;

      (vi) Except as otherwise disclosed in the Prospectus, the Master
   Servicer is not aware and has not received notice that any default, early
   amortization or other performance triggering event has occurred as to any
   other securitization due to any act or failure to act of the Master
   Servicer under such securitization;

      (vii) Except as otherwise disclosed in the Prospectus, the Master
   Servicer has not been terminated as master servicer in a residential
   mortgage loan securitization, either due to a master servicing default or
   to application of a master servicing performance test or trigger;

      (viii) Except as otherwise disclosed in the Prospectus or otherwise in
   writing provided by the Master Servicer to the Depositor, there has been
   no material noncompliance with the applicable servicing criteria with
   respect to other securitizations of residential mortgage loans involving
   the Master Servicer as a master servicer within the past three (3) years;

      (ix) Except as otherwise disclosed in the Prospectus, no material
   changes to the Master Servicer's policies or procedures with respect to
   the master servicing function it will perform under this Agreement for
   mortgage loans of a type similar to the Mortgage Loans have occurred
   during the three-year period immediately preceding the date of this
   Agreement;

      (x) Except as otherwise disclosed in the Prospectus, there is no
   material risk that the Master Servicer's financial condition could affect
   one or more aspects of the performance by the Master Servicer of its
   master servicing obligations under this Agreement in a manner that could
   have a material impact on the performance of the Mortgage Loans or the
   Certificates; and

      (xi) Except as disclosed in the Prospectus, there are no affiliations,
   relationships or transactions relating to the Master Servicer and any
   party identified in Item 1119 of Regulation AB of the type described
   therein.

      It is understood and agreed that the representations and warranties set
forth in this Section 2.03(a) shall survive delivery of the respective Owner
Mortgage Loan Files to the Trustee or the Custodian. Upon discovery by any of
the Depositor, the Master Servicer or the Trustee of a breach of any of the
representations and warranties set forth in this Section 2.03(a), the party
discovering such breach shall give prompt written notice, which shall not
exceed two days, to the other parties. The Master Servicer shall consult with
the Depositor to determine if any such breach is material and any breach
determined by the Depositor to be material shall be included by the Master
Servicer on the next Distribution Date Statement prepared pursuant to Section
4.04.

      (b) The Depositor hereby represents and warrants to the Trustee for the
benefit of Certificateholders that, as of the date of execution of this
Agreement, with respect to the Mortgage Loans, or each Mortgage Loan, as the
case may be:

      (i) The information set forth in the Mortgage Loan Schedule was true
   and correct in all material respects at the date or dates respecting which
   such information is furnished as specified in the Mortgage Loan Schedule;

      (ii) Immediately prior to the transfer and assignment contemplated
   herein, the Depositor was the sole owner and holder of the Mortgage Loan
   free and clear of any and all liens, pledges, charges or security
   interests of any nature and has full right and authority to sell and
   assign the same;

      (iii) The Mortgage is a valid, subsisting and enforceable first lien on
   the property therein described, and the Mortgaged Property is free and
   clear of all encumbrances and liens having priority over the first lien of
   the Mortgage except for liens for real estate taxes and special
   assessments not yet due and payable and liens or interests arising under
   or as a result of any federal, state or local law, regulation or ordinance
   relating to hazardous wastes or hazardous substances, and, if the related
   Mortgaged Property is a condominium unit, any lien for common charges
   permitted by statute or homeowners association fees; and if the Mortgaged
   Property consists of shares of a cooperative housing corporation, any lien
   for amounts due to the cooperative housing corporation for unpaid
   assessments or charges or any lien of any assignment of rents or
   maintenance expenses secured by the real property owned by the cooperative
   housing corporation; and any security agreement, chattel mortgage or
   equivalent document related to, and delivered to the Trustee or to the
   Custodian with, any Mortgage establishes in the Depositor a valid and
   subsisting first lien on the property described therein and the Depositor
   has full right to sell and assign the same to the Trustee;

      (iv) Neither the Depositor nor any prior holder of the Mortgage or the
   related Mortgage Note has modified the Mortgage or the related Mortgage
   Note in any material respect, satisfied, canceled or subordinated the
   Mortgage in whole or in part, released the Mortgaged Property in whole or
   in part from the lien of the Mortgage, or executed any instrument of
   release, cancellation, modification or satisfaction, except in each case
   as is reflected in an agreement delivered to the Trustee or the Custodian
   pursuant to Section 2.01(a);

      (v) All taxes, governmental assessments, insurance premiums, and water,
   sewer and municipal charges, which previously became due and owing have
   been paid, or an escrow of funds has been established, to the extent
   permitted by law, in an amount sufficient to pay for every such item which
   remains unpaid; and the Depositor has not advanced funds, or received any
   advance of funds by a party other than the Mortgagor, directly or
   indirectly (except pursuant to any Subsidy Loan arrangement) for the
   payment of any amount required by the Mortgage, except for interest
   accruing from the date of the Mortgage Note or date of disbursement of the
   Mortgage Loan proceeds, whichever is later, to the day which precedes by
   thirty days the first Due Date under the related Mortgage Note;

      (vi) The Mortgaged Property is undamaged by water, fire, earthquake,
   earth movement other than earthquake, windstorm, flood, tornado or similar
   casualty (excluding casualty from the presence of hazardous wastes or
   hazardous substances, as to which the Depositor makes no representations),
   in a manner which would adversely affect the value of the Mortgaged
   Property as security for the Mortgage Loan or the use for which the
   premises was intended and to the best of the Depositor's knowledge, there
   is no proceeding pending or threatened for the total or partial
   condemnation of the Mortgaged Property;

      (vii) The Mortgaged Property is free and clear of all mechanics' and
   materialmen's liens or liens in the nature thereof; provided, however,
   that this warranty shall be deemed not to have been made at the time of
   the initial issuance of the Certificates if a title policy affording, in
   substance, the same protection afforded by this warranty is furnished to
   the Trustee by the Depositor;

      (viii) Except for Mortgage Loans secured by Co-op Shares and Mortgage
   Loans secured by residential long-term leases, the Mortgaged Property
   consists of a fee simple estate in real property; all of the improvements
   which are included for the purpose of determining the appraised value of
   the Mortgaged Property lie wholly within the boundaries and building
   restriction lines of such property and no improvements on adjoining
   properties encroach upon the Mortgaged Property (unless insured against
   under the related title insurance policy); and to the best of the
   Depositor's knowledge, the Mortgaged Property and all improvements thereon
   comply with all requirements of any applicable zoning and subdivision laws
   and ordinances;

      (ix) The Mortgage Loan meets, or is exempt from, applicable state,
   federal or local laws, regulations and other requirements, pertaining to
   usury, and the Mortgage Loan is not usurious;

      (x) To the best of the Depositor's knowledge, all inspections, licenses
   and certificates required to be made or issued with respect to all
   occupied portions of the Mortgaged Property and, with respect to the use
   and occupancy of the same, including, but not limited to, certificates of
   occupancy and fire underwriting certificates, have been made or obtained
   from the appropriate authorities;

      (xi) All payments required to be made up to the Due Date immediately
   preceding the Cut-Off Date for such Mortgage Loan under the terms of the
   related Mortgage Note have been made and no Mortgage Loan had more than
   one delinquency in the 12 months preceding the Cut-Off Date;

      (xii) The Mortgage Note, the related Mortgage and other agreements
   executed in connection therewith are genuine, and each is the legal, valid
   and binding obligation of the maker thereof, enforceable in accordance
   with its terms, except as such enforcement may be limited by bankruptcy,
   insolvency, reorganization or other similar laws affecting the enforcement
   of creditors' rights generally and by general equity principles
   (regardless of whether such enforcement is considered in a proceeding in
   equity or at law); and, to the best of the Depositor's knowledge, all
   parties to the Mortgage Note and the Mortgage had legal capacity to
   execute the Mortgage Note and the Mortgage and each Mortgage Note and
   Mortgage has been duly and properly executed by the Mortgagor;

      (xiii) Each Mortgage Loan at the time it was originated complied in all
   material respects with applicable federal, state and local laws including,
   without limitation, truth-in-lending, real estate settlement procedures,
   consumer credit protection, equal credit opportunity, predatory and
   abusive lending laws and disclosure laws;

      (xiv) The proceeds of the Mortgage Loans have been fully disbursed,
   there is no requirement for future advances thereunder and any and all
   requirements as to completion of any on-site or off-site improvements and
   as to disbursements of any escrow funds therefor have been complied with
   (except for escrow funds for exterior items which could not be completed
   due to weather and escrow funds for the completion of swimming pools); and
   all costs, fees and expenses incurred in making, closing or recording the
   Mortgage Loan have been paid, except recording fees with respect to
   Mortgages not recorded as of the Closing Date;

      (xv) The Mortgage Loan (except any Mortgage Loan secured by a Mortgaged
   Property located in any jurisdiction, as to which an opinion of counsel of
   the type customarily rendered in such jurisdiction in lieu of title
   insurance is instead received) is covered by an American Land Title
   Association mortgagee title insurance policy or other generally acceptable
   form of policy or insurance acceptable to Fannie Mae or Freddie Mac,
   issued by a title insurer acceptable to Fannie Mae or Freddie Mac insuring
   the originator, its successors and assigns, as to the first priority lien
   of the Mortgage in the original principal amount of the Mortgage Loan and
   subject only to (A) the lien of current real property taxes and
   assessments not yet due and payable, (B) covenants, conditions and
   restrictions, rights of way, easements and other matters of public record
   as of the date of recording of such Mortgage acceptable to mortgage
   lending institutions in the area in which the Mortgaged Property is
   located or specifically referred to in the appraisal performed in
   connection with the origination of the related Mortgage Loan, (C) liens
   created pursuant to any federal, state or local law, regulation or
   ordinance affording liens for the costs of clean-up of hazardous
   substances or hazardous wastes or for other environmental protection
   purposes and (D) such other matters to which like properties are commonly
   subject which do not individually, or in the aggregate, materially
   interfere with the benefits of the security intended to be provided by the
   Mortgage; the Depositor is the sole insured of such mortgagee title
   insurance policy, the assignment to the Trustee of the Depositor's
   interest in such mortgagee title insurance policy does not require any
   consent of or notification to the insurer which has not been obtained or
   made, such mortgagee title insurance policy is in full force and effect
   and will be in full force and effect and inure to the benefit of the
   Trustee, no claims have been made under such mortgagee title insurance
   policy, and no prior holder of the related Mortgage, including the
   Depositor, has done, by act or omission, anything which would impair the
   coverage of such mortgagee title insurance policy;

      (xvi) The Mortgaged Property securing each Mortgage Loan is insured by
   an insurer acceptable to Fannie Mae or Freddie Mac against loss by fire
   and such hazards as are covered under a standard extended coverage
   endorsement, in an amount which is not less than the lesser of 100% of the
   insurable value of the Mortgaged Property and the outstanding principal
   balance of the Mortgage Loan, but in no event less than the minimum amount
   necessary to fully compensate for any damage or loss on a replacement cost
   basis; if the Mortgaged Property is a condominium unit, it is included
   under the coverage afforded by a blanket policy for the project; if upon
   origination of the Mortgage Loan, the improvements on the Mortgaged
   Property were in an area identified in the Federal Register by the Federal
   Emergency Management Agency as having special flood hazards, a flood
   insurance policy meeting the requirements of the current guidelines of the
   Federal Insurance Administration is in effect with a generally acceptable
   insurance carrier, in an amount representing coverage not less than the
   least of (A) the outstanding principal balance of the Mortgage Loan, (B)
   the full insurable value of the Mortgaged Property and (C) the maximum
   amount of insurance which was available under the National Flood Insurance
   Act of 1968, as amended; and each Mortgage obligates the Mortgagor
   thereunder to maintain all such insurance at the Mortgagor's cost and
   expense;

      (xvii) To the best of the Depositor's knowledge, there is no default,
   breach, violation or event of acceleration existing under the Mortgage or
   the related Mortgage Note and no event which, with the passage of time or
   with notice and the expiration of any grace or cure period, would
   constitute a default, breach, violation or event of acceleration; the
   Depositor has not waived any default, breach, violation or event of
   acceleration; and no foreclosure action is currently threatened or has
   been commenced with respect to the Mortgage Loan;

      (xviii) No Mortgage Note or Mortgage is subject to any right of
   rescission, set-off, counterclaim or defense, including the defense of
   usury, nor will the operation of any of the terms of the Mortgage Note or
   Mortgage, or the exercise of any right thereunder, render the Mortgage
   Note or Mortgage unenforceable, in whole or in part, or subject it to any
   right of rescission, set-off, counterclaim or defense, including the
   defense of usury, and no such right of rescission, set-off, counterclaim
   or defense has been asserted with respect thereto;

      (xix) Each Mortgage Note relating to a Mortgage Loan (other than any
   Balloon Loans) is payable in monthly payments, resulting in complete
   amortization of the Mortgage Loan over a term of not more than 360 months;

      (xx) Each Mortgage contains customary and enforceable provisions such
   as to render the rights and remedies of the holder thereof adequate for
   the realization against the Mortgaged Property of the benefits of the
   security, including realization by judicial foreclosure (subject to any
   limitation arising from any bankruptcy, insolvency or other law for the
   relief of debtors), and there is no homestead or other exemption available
   to the Mortgagor which would interfere with such right of foreclosure;

      (xxi) To the best of the Depositor's knowledge, no Mortgagor is a
   debtor in any state or federal bankruptcy or insolvency proceeding;

      (xxii) Each Mortgaged Property is located in the United States and
   consists of a one- to four-unit residential property, which may include a
   detached home, townhouse, condominium unit or a unit in a planned unit
   development or, in the case of Mortgage Loans secured by Co-op Shares,
   leases or occupancy agreements;

      (xxiii) The Mortgage Loan is a "qualified mortgage" within the meaning
   of Section 860G(a)(3) of the Code;

      (xxiv) With respect to each Mortgage where a lost note affidavit has
   been delivered to the Custodian in place of the related Mortgage Note, the
   related Mortgage Note is no longer in existence;

      (xxv) In the event that the Mortgagor is an inter vivos "living" trust,
   (i) such trust is in compliance with Fannie Mae or Freddie Mac standards
   for inter vivos trusts and (ii) holding title to the Mortgaged Property in
   such trust will not diminish any rights as a creditor including the right
   to full title to the Mortgaged Property in the event foreclosure
   proceedings are initiated;

      (xxvi) If the Mortgage Loan is secured by a long-term residential
   lease, (1) the lessor under the lease holds a fee simple interest in the
   land; (2) the terms of such lease expressly permit the mortgaging of the
   leasehold estate, the assignment of the lease without the lessor's consent
   and the acquisition by the holder of the Mortgage of the rights of the
   lessee upon foreclosure or assignment in lieu of foreclosure or provide
   the holder of the Mortgage with substantially similar protections; (3) the
   terms of such lease do not (a) allow the termination thereof upon the
   lessee's default without the holder of the Mortgage being entitled to
   receive written notice of, and opportunity to cure, such default, (b)
   allow the termination of the lease in the event of damage or destruction
   as long as the Mortgage is in existence, (c) prohibit the holder of the
   Mortgage from being insured (or receiving proceeds of insurance) under the
   hazard insurance policy or policies relating to the Mortgaged Property or
   (d) permit any increase in rent other than pre-established increases set
   forth in the lease; (4) the original term of such lease is not less than
   15 years; (5) the term of such lease does not terminate earlier than five
   years after the maturity date of the Mortgage Note; and (6) the Mortgaged
   Property is located in a jurisdiction in which the use of leasehold
   estates in transferring ownership in residential properties is a widely
   accepted practice;

      (xxvii) No Mortgage Loan is a "high cost" loan as defined under any
   federal, state or local law applicable to such Mortgage Loan at the time
   of its origination;

      (xxviii) No Mortgage Loan is serviced by the Trustee or an affiliate of
   the Trustee;

      (xxix) No Mortgage Loan (other than a Mortgage Loan that is a New
   Jersey covered purchase loan) is a High Cost Loan or Covered Loan, as
   applicable (as such terms are defined in the then current S&P's LEVELS(R)
   Glossary which is now Version 6.1 Revised, Appendix E) and no Mortgage
   Loan originated on or after October 1, 2002 through March 6, 2003 is
   governed by the Georgia Fair Lending Act;

      (xxx) No error, omission, misrepresentation, negligence, fraud or
   similar occurrence with respect to a Mortgage Loan has taken place on the
   part of Wells Fargo Bank, as an originator, or the Mortgagor (except with
   respect to the accuracy of Unverified Information), or to the best of the
   Depositor's knowledge, any appraiser, any builder, or any developer, or
   any other party involved in the origination of the Mortgage Loan or in the
   application of any insurance in relation to such Mortgage Loan;

      (xxxi) The Mortgage Loan was underwritten in accordance with the
   applicable Underwriting Guidelines in effect at the time of origination
   with exceptions thereto exercised in a reasonable manner; and

      (xxxii) There is an appraisal of each Mortgaged Property. The appraisal
   was conducted by an appraiser who had no interest, direct or indirect, in
   the Mortgaged Property or in any loan made on the security thereof, and
   whose compensation is not affected by the approval or disapproval of the
   Mortgage Loan and the appraisal and the appraiser both satisfy the
   applicable requirements of Title XI of the Financial Institution Reform,
   Recover, and Enforcement Act of 1989 and the regulations promulgated
   thereunder, all as in effect on the date the Mortgage Loan was originated.

      Notwithstanding the foregoing, no representations or warranties are
made by the Depositor as to the environmental condition of any Mortgaged
Property; the absence, presence or effect of hazardous wastes or hazardous
substances on any Mortgaged Property; any casualty resulting from the
presence or effect of hazardous wastes or hazardous substances on, near or
emanating from any Mortgaged Property; the impact on Certificateholders of
any environmental condition or presence of any hazardous substance on or near
any Mortgaged Property; or the compliance of any Mortgaged Property with any
environmental laws, nor is any agent, person or entity otherwise affiliated
with the Depositor authorized or able to make any such representation,
warranty or assumption of liability relative to any Mortgaged Property.

      It is understood and agreed that the representations and warranties set
forth in this Section 2.03(b) shall survive delivery of the respective Owner
Mortgage Loan Files (and Retained Mortgage Loan Files, if applicable) to the
Custodian and shall inure to the benefit of the Trustee notwithstanding any
restrictive or qualified endorsement or assignment.

      (c) Upon discovery by any of the Depositor, the Master Servicer, the
Trustee or the Custodian that any of the representations and warranties made
in subsection (b) above is not accurate (referred to herein as a "breach")
and, except for a breach of the representation and warranty set forth in
subsection (b)(i), where such breach is a result of the Cut-Off Date
Principal Balance of a Mortgage Loan being greater, by $25,000 or greater,
than the Cut-Off Date Principal Balance of such Mortgage Loan indicated on
the Mortgage Loan Schedule, that such breach materially and adversely affects
the interests of the Certificateholders in the related Mortgage Loan, the
party discovering such breach shall give prompt written notice (not to exceed
two days after discovery) to the other parties to this Agreement and the
Custodian (any Custodian being so obligated under a Custodial Agreement).
Within 60 days of the earlier of its discovery or its receipt of notice of
any such breach, the Depositor shall cure such breach in all material
respects or shall either (i) repurchase the Mortgage Loan or any property
acquired in respect thereof from the Trust Estate at a price equal to the
Repurchase Price; provided that if the Depositor elects to repurchase a
Mortgage Loan due to a breach of the representation and warranty set forth in
subsection (b)(i), where such breach is a result of the Cut-Off Date
Principal Balance of a Mortgage Loan being greater, by $25,000 or greater,
than the Cut-Off Date Principal Balance of such Mortgage Loan indicated on
the Mortgage Loan Schedule, such repurchase is only permitted within 90 days
of the Closing Date or (ii) if within two years of the Startup Day, or such
other period permitted by the REMIC Provisions, substitute for such Mortgage
Loan in the manner described in Section 2.02. In addition to the foregoing,
if a breach of the representation set forth in clause (b)(xiii) or (xxix) of
this Section 2.03 occurs as a result of a violation of an applicable
predatory or abusive lending law, the Depositor shall reimburse the Trust for
all costs and damages including, but not limited to, reasonable attorneys'
fees and costs, incurred by the Trust as a result of the violation of such
law (such amount, the "Reimbursement Amount"). The Repurchase Price, the
Substitution Principal Amount, if any, plus accrued interest thereon and the
other amounts referred to in Section 2.02, and any Reimbursement Amount shall
be deposited in the Certificate Account. It is understood and agreed, except
with respect to the second preceding sentence, that the obligation of the
Depositor to repurchase or substitute for any Mortgage Loan or property as to
which such a breach has occurred and is continuing shall constitute the sole
remedy respecting such breach available to Certificateholders or the Trustee
on behalf of Certificateholders, and such obligation shall survive until
termination of the Trust Estate hereunder.

      The Trustee shall be responsible for enforcing the Depositor's
obligations under this Section 2.03. If the Trustee receives written notice
from the Master Servicer or the Custodian that such breach is not cured by
the Depositor within 60 days after the Trustee's notice, the Trustee shall
enforce the Depositor's obligation to repurchase such Mortgage Loan or
substitute for such Mortgage Loan in accordance with the provisions of this
Section 2.03. In connection with any substitution permitted by this Section
2.03, the Master Servicer shall verify that the unpaid principal balance and
the Loan-to-Value Ratio of the Substitute Mortgage Loan satisfy the
requirements for a Substitute Mortgage Loan set forth in the third paragraph
of Section 2.02.

      Section 2.04 Execution and Delivery of Certificates.

      The Trustee acknowledges the assignment to it of the Mortgage Loans and
the delivery of the Owner Mortgage Loan Files to the Custodian, on behalf of
the Trustee. The Paying Agent, concurrently with such delivery, has executed
and delivered to or upon the order of the Depositor, in exchange for the
Mortgage Loans, together with all other assets included in the definition of
"Trust Estate," receipt of which is hereby acknowledged, Certificates in
authorized denominations which evidence ownership of the entire Trust Estate.

      Section 2.05 Designation of Certificates; Designation of Startup Day
and Latest Possible Maturity Date.

      The Depositor hereby designates the Classes of Class A Certificates
(other than the Exchangeable Certificates and the Residual Certificate) and
the Classes of Class B Certificates as classes of "regular interests" and the
Class A-R Certificate as the single class of "residual interest" in the REMIC
for the purposes of Code Sections 860G(a)(1) and 860G(a)(2), respectively.
The Closing Date is hereby designated as the "Startup Day" of the REMIC
within the meaning of Code Section 860G(a)(9). The "latest possible maturity
date" of the regular interests in the REMIC is January 25, 2038 for purposes
of Code Section 860G(a)(1).

                                   ARTICLE III

                  ADMINISTRATION OF THE TRUST ESTATE; SERVICING
                              OF THE MORTGAGE LOANS

      Section 3.01 Certificate Account.

      (a) The Master Servicer shall establish and maintain a Certificate
Account for the deposit of funds received by the Master Servicer with respect
to the Mortgage Loans serviced by each Servicer pursuant to each of the
Servicing Agreements. Such account shall be maintained as an Eligible
Account. The Master Servicer shall give notice to each Servicer and the
Depositor of the location of the Certificate Account and of any change in the
location thereof.

      (b) The Master Servicer shall deposit into the Certificate Account on
the day of receipt thereof all amounts received by it from any Servicer
pursuant to any of the Servicing Agreements and shall, in addition, deposit
into the Certificate Account the following amounts, in the case of amounts
specified in clauses (i) and (iii), not later than the Business Day preceding
the Distribution Date on which such amounts are required to be distributed to
Certificateholders and, in the case of the amounts specified in clause (ii),
not later than the Business Day next following the day of receipt and posting
by the Master Servicer:

      (i) Periodic Advances pursuant to Section 3.03(a) made by the Master
   Servicer or the Trustee, if any and any amounts deemed received by the
   Master Servicer pursuant to Section 3.01(d);

      (ii) in the case of any Mortgage Loan that is repurchased by the
   Depositor pursuant to Section 2.02, 2.03, 3.08 or 9.01 or that is
   auctioned by the Master Servicer pursuant to Section 3.08, the purchase
   price therefor or, where applicable, any Substitution Principal Amount and
   any amounts received in respect of the interest portion of unreimbursed
   Periodic Advances; and

      (iii) any Compensating Interest for such Distribution Date.

      (c) The Master Servicer may cause the funds in the Certificate Account
to be invested in Eligible Investments. No such Eligible Investments will be
sold or disposed of at a gain prior to maturity unless the Master Servicer
has received an Opinion of Counsel or other evidence satisfactory to it that
such sale or disposition will not cause the Trust Estate to be subject to any
Prohibited Transactions Tax, otherwise subject the Trust Estate to tax, or
cause the REMIC to fail to qualify as a REMIC while any Certificates are
outstanding. Any amounts deposited in the Certificate Account prior to the
Distribution Date may be invested for the account of the Master Servicer and
any investment income thereon shall be additional compensation to the Master
Servicer for services rendered under this Agreement. The amount of any losses
incurred in respect of any such investments shall be deposited in the
Certificate Account by the Master Servicer out of its own funds immediately
as realized, without any right of reimbursement therefor from the Trust
Estate.

      (d) For purposes of this Agreement, the Master Servicer will be deemed
to have received from a Servicer on the applicable Remittance Date for such
funds all amounts deposited by such Servicer into the Custodial P&I Account
maintained in accordance with the applicable Servicing Agreement, if such
Custodial P&I Account is not an Eligible Account as defined in this
Agreement, to the extent such amounts are not actually received by the Master
Servicer on such Remittance Date as a result of the bankruptcy, insolvency,
receivership or other financial distress of the depository institution in
which such Custodial P&I Account is being held. To the extent that amounts so
deemed to have been received by the Master Servicer are subsequently remitted
to the Master Servicer, the Master Servicer shall be entitled to retain such
amounts.

      Section 3.02 Permitted Withdrawals from the Certificate Account.

      (a) The Master Servicer may, from time to time, make withdrawals from
the Certificate Account for the following purposes (limited, in the case of
Servicer reimbursements, to cases where funds in the respective Custodial P&I
Account are not sufficient therefor):

      (i) to reimburse the Master Servicer or the Trustee for Periodic
   Advances made by the Master Servicer or the Trustee pursuant to Section
   3.03(a) or any Servicer for Periodic Advances made and Capitalized Advance
   Amounts created pursuant to any Servicing Agreement with respect to
   previous Distribution Dates, such right to reimbursement pursuant to this
   subclause (i) being limited to amounts received on or in respect of
   particular Mortgage Loans (including, for this purpose, Liquidation
   Proceeds, REO Proceeds and proceeds from the purchase, sale, repurchase or
   substitution of Mortgage Loans pursuant to Section 2.02, 2.03, 3.08 or
   9.01) with respect to which such Periodic Advances were made or
   Capitalized Advance Amounts were created;

      (ii) to reimburse any Servicer, the Master Servicer or the Trustee for
   any Periodic Advances determined in good faith to have become
   Nonrecoverable Advances; provided, however, that any portion of
   Nonrecoverable Advances representing Fixed Retained Yield shall be
   reimbursable only from amounts constituting Fixed Retained Yield and not
   from assets of the Trust Estate;

      (iii) to reimburse the Master Servicer or any Servicer from Liquidation
   Proceeds for Liquidation Expenses and for amounts expended by the Master
   Servicer or any Servicer pursuant hereto or to any Servicing Agreement,
   respectively, in good faith in connection with the restoration of damaged
   property or for foreclosure expenses;

      (iv) from any Mortgagor payment on account of interest or other
   recovery (including Net REO Proceeds) with respect to a particular
   Mortgage Loan, to pay the Master Servicing Fee with respect to such
   Mortgage Loan to the Master Servicer;

      (v) to reimburse the Master Servicer, any Servicer or the Trustee (or,
   in certain cases, the Depositor) for expenses incurred by it (including
   taxes paid on behalf of the Trust Estate) and recoverable by or
   reimbursable to it pursuant to Section 3.03(c), Section 6.03, the second
   or third paragraphs of Section 8.06 or the third sentence of Section
   8.13(a) or pursuant to such Servicer's Servicing Agreement, provided such
   expenses are "unanticipated" within the meaning of the REMIC Provisions;

      (vi) to pay to the Depositor or other purchaser with respect to each
   Mortgage Loan or property acquired in respect thereof that has been
   repurchased or replaced pursuant to Section 2.02, 2.03, 3.08 or 9.01 or
   auctioned pursuant to Section 3.08, all amounts received thereon and not
   required to be distributed as of the date on which the related repurchase
   or purchase price or Scheduled Principal Balance was determined;

      (vii) to remit funds to the Paying Agent in the amounts and in the
   manner provided for herein;

      (viii) to pay to the Master Servicer any interest earned on or
   investment income with respect to funds in the Certificate Account;

      (ix) to pay to the Master Servicer or any Servicer out of Liquidation
   Proceeds allocable to interest the amount of any unpaid Master Servicing
   Fee or Servicing Fee (as adjusted pursuant to the related Servicing
   Agreement) and any unpaid assumption fees, late payment charges or other
   Mortgagor charges on the related Mortgage Loan;

      (x) to pay to the Master Servicer as additional master servicing
   compensation any Liquidation Profits which a Servicer is not entitled to
   pursuant to the applicable Servicing Agreement;

      (xi) to withdraw from the Certificate Account any amount deposited in
   the Certificate Account that was not required to be deposited therein;

      (xii) to clear and terminate the Certificate Account pursuant to
   Section 9.01; and

      (xiii) to pay to Wells Fargo Bank from any Mortgagor payment on account
   of interest or other recovery (including Net REO Proceeds) with respect to
   a particular Mortgage Loan, the Fixed Retained Yield, if any, with respect
   to such Mortgage Loan; provided, however, that with respect to any payment
   of interest received by the Master Servicer in respect of a Mortgage Loan
   (whether paid by the Mortgagor or received as Liquidation Proceeds,
   Insurance Proceeds or otherwise) which is less than the full amount of
   interest then due with respect to such Mortgage Loan, only that portion of
   such payment of interest that bears the same relationship to the total
   amount of such payment of interest as the Fixed Retained Yield Rate, if
   any, in respect of such Mortgage Loan bears to the Mortgage Interest Rate
   shall be allocated to the Fixed Retained Yield with respect thereto.

      (b) The Master Servicer shall keep and maintain separate accounting, on
a Mortgage Loan by Mortgage Loan basis, for the purpose of justifying any
payment to and withdrawal from the Certificate Account. The Master Servicer
shall notify the Depositor and the Trustee of the amount, purpose and party
paid pursuant to Section 3.02(a)(v).

      Section 3.03 Advances by Master Servicer and Trustee.

      (a) In the event an Other Servicer fails to make any required Periodic
Advances of principal and interest on a Mortgage Loan as required by the
related Other Servicing Agreement prior to the Business Day preceding the
Distribution Date occurring in the month during which such Periodic Advance
is due, the Master Servicer shall make Periodic Advances to the extent
provided hereby. In the event Wells Fargo Bank in its capacity as Servicer
fails to make any required Periodic Advances of principal and interest on a
Mortgage Loan as required by the Wells Fargo Bank Servicing Agreement prior
to the Business Day preceding the Distribution Date occurring in the month
during which such Periodic Advance is due, the Trustee shall, to the extent
required by Section 8.14, make such Periodic Advance to the extent provided
hereby, provided that the Trustee has previously received the certificate of
the Master Servicer described in the following sentence. The Master Servicer
shall certify to the Trustee with respect to any such Distribution Date (i)
the amount of Periodic Advances required of Wells Fargo Bank in its capacity
as Servicer or such Other Servicer, as the case may be, (ii) the amount
actually advanced by Wells Fargo Bank in its capacity as Servicer or such
Other Servicer, (iii) the amount that the Trustee or Master Servicer is
required to advance hereunder and (iv) whether the Master Servicer has
determined that it reasonably believes that such Periodic Advance is a
Nonrecoverable Advance. Amounts advanced by the Trustee or Master Servicer
shall be deposited in the Certificate Account on the Business Day preceding
the related Distribution Date. Notwithstanding the foregoing, neither the
Master Servicer nor the Trustee will be obligated to make a Periodic Advance
that it reasonably believes to be a Nonrecoverable Advance. The Trustee may
conclusively rely for any determination to be made by it hereunder upon the
determination of the Master Servicer as set forth in its certificate.

      (b) To the extent an Other Servicer fails to make an advance on account
of the taxes or insurance premiums with respect to a Mortgage Loan required
pursuant to the related Other Servicing Agreement, the Master Servicer shall,
if the Master Servicer has actual knowledge of such failure of the Servicer,
advance such funds and take such steps as are necessary to pay such taxes or
insurance premiums. To the extent Wells Fargo Bank in its capacity as
Servicer fails to make an advance on account of the taxes or insurance
premiums with respect to a Mortgage Loan required pursuant to the Wells Fargo
Bank Servicing Agreement, the Master Servicer shall, if the Master Servicer
knows of such failure of Wells Fargo Bank in its capacity as Servicer,
certify to the Trustee that such failure has occurred. Upon receipt of such
certification, the Trustee shall advance such funds and take such steps as
are necessary to pay such taxes or insurance premiums.

      (c) The Master Servicer and the Trustee shall each be entitled to be
reimbursed from the Certificate Account for any Periodic Advance made by it
under Section 3.03(a) to the extent described in Section 3.02(a)(i) and
(a)(ii). The Master Servicer and the Trustee shall be entitled to be
reimbursed pursuant to Section 3.02(a)(v) for any advance by it pursuant to
Section 3.03(b). The Master Servicer shall diligently pursue restoration of
such amount to the Certificate Account from the related Servicer. The Master
Servicer shall, to the extent it has not already done so, upon the request of
the Trustee, withdraw from the Certificate Account and remit to the Trustee
any amounts to which the Trustee is entitled as reimbursement pursuant to
Section 3.02 (a)(i), (ii) and (v).

      (d) Except as provided in Section 3.03(a) and (b), neither the Master
Servicer nor the Trustee shall be required to pay or advance any amount which
any Servicer was required, but failed, to deposit in the Certificate Account.

      Section 3.04 Custodian to Cooperate; Release of Owner Mortgage Loan
Files and Retained Mortgage Loan Files.

      In connection with the deposit by a Servicer into the Certificate
Account of the proceeds from a Liquidated Loan or of a Prepayment in Full,
the Master Servicer or applicable Servicer shall confirm that all amounts
required to be remitted to the Certificate Account in connection with such
Mortgage Loan have been so deposited, and the Master Servicer or applicable
Servicer shall deliver two copies of any related Request for Release to the
Custodian. The Custodian shall, within five Business Days of its receipt of
such a Request for Release, release the related Owner Mortgage Loan File (and
Retained Mortgage Loan File, if applicable) to the Master Servicer or such
Servicer, as requested by the Master Servicer or such Servicer. No expenses
incurred in connection with any instrument of satisfaction or deed of
reconveyance shall be chargeable to the Certificate Account.

      From time to time and as appropriate for the servicing or foreclosure
of any Mortgage Loan, including but not limited to, collection under any
insurance policies, or to effect a partial release of any Mortgaged Property
from the lien of the Mortgage, the Servicer of such Mortgage Loan shall
deliver to the Master Servicer or Custodian two copies of a Request for
Release. Upon the Master Servicer's receipt of any such Request for Release,
the Master Servicer shall promptly forward such request in hard copy or in
electronic format acceptable to the Custodian. The Custodian shall, within
five Business Days, release the related Owner Mortgage Loan File (and
Retained Mortgage Loan File, if applicable) to the Master Servicer or such
Servicer. Any such Request for Release shall obligate the Master Servicer or
such Servicer, as the case may be, to return the Owner Mortgage Loan File
(and Retained Mortgage Loan File, if applicable) to the Custodian by the
sixtieth day following the release thereof, unless (i) the Mortgage Loan has
been liquidated and the Liquidation Proceeds relating to the Mortgage Loan
have been deposited in the Certificate Account or (ii) the Owner Mortgage
Loan File (and Retained Mortgage Loan File, if applicable) or such document
has been delivered to an attorney, or to a public trustee or other public
official as required by law, for purposes of initiating or pursuing legal
action or other proceedings for the foreclosure of the Mortgaged Property
either judicially or non-judicially. Upon receipt of two copies of a Request
for Release stating that such Mortgage Loan was liquidated and that all
amounts received or to be received in connection with such liquidation which
are required to be deposited into the Certificate Account have been so
deposited, or that such Mortgage Loan has become an REO Mortgage Loan, the
Custodian shall amend its records.

      Upon the occurrence of the event specified in clause (ii) of the
preceding paragraph, the Trustee shall execute and deliver to the Master
Servicer or such Servicer, as directed by the Master Servicer, court
pleadings, requests for trustee's sale or other documents necessary to the
foreclosure or trustee's sale in respect of a Mortgaged Property or to any
legal action brought to obtain judgment against any Mortgagor on the Mortgage
Note or Mortgage or to obtain a deficiency judgment, or to enforce any other
remedies or rights provided by the Mortgage Note or Mortgage or otherwise
available at law or in equity. Each such certification shall include a
request that such pleadings or documents be executed by the Trustee and a
statement as to the reason such documents or pleadings are required and that
the execution and delivery thereof by the Trustee will not invalidate or
otherwise affect the lien of the Mortgage, except for the termination of such
a lien upon completion of the foreclosure proceeding or trustee's sale.

      Section 3.05 Annual Compliance Statements.

      The Master Servicer shall deliver in electronic form, or otherwise make
available to the Depositor and the Trustee, and the Master Servicer shall
cause each Additional Master Servicer engaged by it and each Servicer to
deliver, in electronic form, or otherwise make available, to the Master
Servicer, the Trustee and each Rating Agency on or before March 5 of each
year or if such day is not a Business Day, the next Business Day (with a 10
calendar day cure period, but in no event later than March 15), commencing in
March 2008, a copy of a certificate (followed by a hard copy to the party or
parties receiving such certificate within 10 calendar days) in the form
required by Item 1123 of Regulation AB, to the effect that (i) an authorized
officer of the Master Servicer, the Additional Master Servicer or the
applicable Servicer, as the case may be, has reviewed (or a review has been
made under his or her supervision of) such party's activities under this
Agreement or the applicable Servicing Agreement, in the case of a Servicer,
or such other applicable agreement in the case of an Additional Master
Servicer, during the prior calendar year or portion thereof and (ii) to the
best of such officer's knowledge, based on such review, such party has
fulfilled all of its obligations under this Agreement or the applicable
Servicing Agreement, in the case of a Servicer, or such other applicable
agreement in the case of an Additional Master Servicer, in all material
respects throughout the prior calendar year or portion thereof or, if there
has been a failure to fulfill any such obligation in any material respect,
specifying each such failure known to such officer and the nature and status
thereof. If any of the certificates delivered pursuant to this Section 3.05
disclose that there has been a failure to fulfill any obligation in any
material respect then the Master Servicer shall promptly notify the Depositor
and forward a copy of such certificate to the Depositor, and the Depositor
shall review such certificate and, if applicable, consult with the Master
Servicer as to the nature of any failure to fulfill any obligation under this
Agreement or the applicable Servicing Agreement, in the case of a Servicer,
or such other applicable agreement in the case of an Additional Master
Servicer, in any material respect.

      Section 3.06 Title, Management and Disposition of Any REO Mortgage Loan.

      The Master Servicer shall enforce the obligations of the applicable
Servicer to administer each REO Mortgage Loan at all times so that each REO
Mortgage Loan qualifies as "foreclosure property" under the REMIC Provisions
and that it does not earn any "net income from foreclosure property" which is
subject to tax under the REMIC Provisions. In the event that a Servicer is
unable to dispose of any REO Mortgage Loan within the period mandated by each
of the Servicing Agreements, the Master Servicer shall monitor such Servicer
to verify that such REO Mortgage Loan is auctioned to the highest bidder
within the period so specified. In the event of any such sale of a REO
Mortgage Loan, the Custodian shall, at the written request of the Master
Servicer and upon being supported with appropriate forms therefor, within
five Business Days of the deposit by the Master Servicer of the proceeds of
such sale or auction into the Certificate Account, release or cause to be
released to the entity identified by the Master Servicer the related Owner
Mortgage Loan File, Retained Mortgage Loan File, if applicable, and Servicer
Mortgage Loan File and shall execute and deliver such instruments of transfer
or assignment, in each case without recourse, as shall be necessary to vest
in the auction purchaser title to the REO Mortgage Loan and the Custodian
shall have no further responsibility with regard to such Owner Mortgage Loan
File, Retained Mortgage Loan File, if applicable, or Servicer Mortgage Loan
File. Neither the Trustee, the Master Servicer nor any Servicer, acting on
behalf of the Trust Estate, shall provide financing from the Trust Estate to
any purchaser of an REO Mortgage Loan.

      Section 3.07 Amendments to Servicing Agreements, Modification of
Standard Provisions.

      (a) Subject to the prior written consent of the Trustee pursuant to
Section 3.07(b) and the prior written consent of the Depositor, the Master
Servicer may, from time to time, to the extent permitted by the applicable
Servicing Agreement, make such modifications and amendments to such Servicing
Agreement as the Master Servicer deems necessary or appropriate to confirm or
carry out more fully the intent and purpose of such Servicing Agreement and
the duties, responsibilities and obligations to be performed by the
applicable Servicer thereunder. Such modifications may only be made if they
are consistent with the REMIC Provisions, as evidenced by an Opinion of
Counsel. Prior to the issuance of any modification or amendment, the Master
Servicer shall deliver to the Trustee and the Depositor such Opinion of
Counsel and an Officer's Certificate setting forth (i) the provision that is
to be modified or amended, (ii) the modification or amendment that the Master
Servicer desires to issue and (iii) the reason or reasons for such proposed
amendment or modification.

      (b) The Trustee shall consent to any amendment or supplement to a
Servicing Agreement proposed by the Master Servicer pursuant to Section
3.07(a), which consent and amendment shall not require the consent of any
Certificateholder if it is (i) for the purpose of curing any mistake or
ambiguity, to further effect or protect the rights of the Certificateholders
or (ii) for any other purpose, provided such amendment or supplement for such
other purpose cannot reasonably be expected to adversely affect
Certificateholders. The lack of reasonable expectation of an adverse effect
on Certificateholders may be established through the delivery to the Trustee
of (i) an Opinion of Counsel to such effect or (ii) written notification from
each Rating Agency to the effect that such amendment or supplement will not
result in reduction of the current rating assigned by that Rating Agency to
the Certificates. Notwithstanding the two immediately preceding sentences,
the Trustee may, in its discretion, decline to enter into or consent to any
such supplement or amendment if its own rights, duties or immunities shall be
adversely affected.

      (c)(i) Notwithstanding anything to the contrary in this Section 3.07,
the Master Servicer from time to time may, without the consent of any
Certificateholder or the Trustee, enter into an amendment (A) to an Other
Servicing Agreement for the purpose of (i) eliminating or reducing Month End
Interest and (ii) providing for the remittance of Full Unscheduled Principal
Receipts by the applicable Servicer to the Master Servicer not later than the
24th day of each month (or if such day is not a Business Day, on the previous
Business Day), (B) to the Wells Fargo Bank Servicing Agreement for the
purpose of changing the applicable Remittance Date to the 18th day of each
month (or if such day is not a Business Day, on the previous Business Day) or
(C) to a Servicing Agreement for the purpose of effecting or facilitating
compliance by the applicable Servicer with Regulation AB or to conform a
Servicing Agreement to industry practices relating to Regulation AB.

      (ii) The Master Servicer may direct Wells Fargo Bank in its capacity as
   Servicer to enter into an amendment to the Wells Fargo Bank Servicing
   Agreement for the purposes described in Section 3.07(c)(i)(B) or (C).

      Section 3.08 Oversight of Servicing.

      The Master Servicer shall supervise, monitor and oversee the servicing
of the Mortgage Loans by each Servicer and the performance by each Servicer
of all services, duties, responsibilities and obligations (including the
obligation to maintain an Errors and Omissions Policy and Fidelity Bond) that
are to be observed or performed by the Servicer under its respective
Servicing Agreement. In performing its obligations hereunder, the Master
Servicer shall act in a manner consistent with Accepted Master Servicing
Practices and in a manner consistent with the terms and provisions of any
insurance policy required to be maintained by the Master Servicer or any
Servicer pursuant to this Agreement or any Servicing Agreement. The Master
Servicer acknowledges that prior to taking certain actions required to
service the Mortgage Loans, each Servicing Agreement provides that the
Servicer thereunder must notify, consult with, obtain the consent of, waiver
from, or otherwise follow the instructions of the Master Servicer. In the
case of any request for waiver from a Servicer, the Master Servicer shall
promptly instruct such Servicer or otherwise respond to such Servicer's
request. The Master Servicer shall not waive compliance by a Servicer with
those provisions of its Servicing Agreement which are required to enable the
Depositor and the Master Servicer to satisfy the Trust's ongoing reporting
obligations under the Exchange Act. In addition, in no event will the Master
Servicer instruct such Servicer to take any action, give any consent to
action by such Servicer or waive compliance by such Servicer with any
provision of such Servicer's Servicing Agreement if any resulting action or
failure to act would be inconsistent with the requirements of the Rating
Agencies that rated the Certificates, would be inconsistent with the
requirements of Regulation AB or would otherwise have an adverse effect on
the Certificateholders. Any such action or failure to act shall be deemed to
have an adverse effect on the Certificateholders if such action or failure to
act either results in (i) the downgrading of the rating assigned by either
Rating Agency to the Certificates, (ii) the loss by the Trust Estate of REMIC
status for federal income tax purposes or (iii) the imposition of any
Prohibited Transaction Tax or any federal taxes on either of the REMIC or the
Trust Estate. The Master Servicer shall have full power and authority in its
sole discretion to take any action with respect to the Trust Estate as may be
necessary or advisable to avoid the circumstances specified including clause
(ii) or (iii) of the preceding sentence.

      For the purposes of determining whether any modification of a Mortgage
Loan shall be permitted by the Master Servicer, such modification shall be
construed as a substitution of the modified Mortgage Loan for the Mortgage
Loan originally deposited in the Trust Estate if it would be a "significant
modification" within the meaning of Section 1.860G-2(b) of the regulations of
the U.S. Department of the Treasury. No modification shall be approved unless
(i) the modified Mortgage Loan would qualify as a Substitute Mortgage Loan
under Section 2.02 and (ii) with respect to any modification that occurs more
than three months after the Closing Date and is not the result of a default
or a reasonably foreseeable default under the Mortgage Loan, there is
delivered to the Trustee an Opinion of Counsel (at the expense of the party
seeking to modify the Mortgage Loan) to the effect that such modification
would not be treated as giving rise to a new debt instrument for federal
income tax purposes as described in the preceding sentence; provided,
however, that no such Opinion of Counsel need be delivered if the sole
purpose of the modification is to reduce the Monthly Payment on a Mortgage
Loan as a result of a Curtailment such that the Mortgage Loan is fully
amortized by its original maturity date.

      During the term of this Agreement, the Master Servicer shall consult
fully with each Servicer as may be necessary from time to time to perform and
carry out the Master Servicer's obligations hereunder and otherwise exercise
reasonable efforts to cause such Servicer to perform and observe the
covenants, obligations and conditions to be performed or observed by it under
its Servicing Agreement.

      The relationship of the Master Servicer to the Trustee under this
Agreement is intended by the parties to be that of an independent contractor
and not that of a joint venturer, partner or agent.

      The Master Servicer shall administer the Trust Estate on behalf of the
Trustee and shall have full power and authority, acting alone or (subject to
the requirements of Section 6.06) through one or more Subcontractors, to do
any and all things in connection with such administration which it may deem
necessary or desirable. Upon the execution and delivery of this Agreement,
and from time to time as may be required thereafter, the Trustee shall
furnish the Master Servicer or its Subcontractors with any powers of attorney
and such other documents as may be necessary or appropriate to enable the
Master Servicer to carry out its administrative duties hereunder.

      The Depositor shall have a limited option to repurchase any defaulted
Mortgage Loan or REO Mortgage Loan during the following time periods: (i)
beginning on the first day of the second month following the month in which
the Master Servicer has reported that a Servicer has initiated foreclosure
proceedings with respect to such a defaulted Mortgage Loan, with such
repurchase option expiring on the last day of such second following month;
(ii) beginning on the first day of the second month following the month in
which the Master Servicer has reported that such defaulted Mortgage Loan has
become an REO Mortgage Loan, with such repurchase option expiring on the last
day of such second following month; and (iii) beginning on the day on which a
Servicer accepts a contractual commitment by a third party to purchase the
Mortgaged Property related to the defaulted Mortgage Loan or REO Mortgage
Loan, with such repurchase option expiring on the earlier of the last day of
the month in which such contractual commitment was accepted by the Servicer
or the day immediately prior to the day on which the closing occurs with
respect to such third party purchase of the Mortgaged Property related to the
defaulted Mortgage Loan or REO Mortgage Loan. The Depositor shall be entitled
to repurchase at its option any Mortgage Loan in the Trust Estate which,
pursuant to paragraph 5(b) of the Mortgage Loan Purchase Agreement, Wells
Fargo Bank requests the Depositor to repurchase and to sell to Wells Fargo
Bank to facilitate the exercise of Wells Fargo Bank's rights against the
originator or a prior holder of such Mortgage Loan. The purchase price for
any Mortgage Loan repurchased pursuant to this paragraph shall be the
Repurchase Price. Upon the receipt of such Repurchase Price, the Master
Servicer shall provide to the Trustee the certification required by Section
3.04 and the Trustee and the Custodian, if any, shall promptly release to the
Depositor the Owner Mortgage Loan File and Retained Mortgage Loan File, if
applicable, relating to the Mortgage Loan being repurchased.

      In the event that (i) the Master Servicer determines at any time that,
notwithstanding the representations and warranties set forth in Section
2.03(b), any Mortgage Loan is not a "qualified mortgage" within the meaning
of Section 860G of the Code and (ii) the Trustee is unable to enforce the
obligation of the Depositor to purchase such Mortgage Loan pursuant to
Section 2.02 within two months of such determination, the Master Servicer
shall cause such Mortgage Loan to be auctioned to the highest bidder and sold
out of the Trust Estate no later than the date 90 days after such
determination. In the event of any such sale of a Mortgage Loan, the
Custodian shall, at the written request of the Master Servicer and upon being
supported with appropriate forms therefor, within five Business Days of the
deposit by the Master Servicer of the proceeds of such auction into the
Certificate Account, release or cause to be released to the entity identified
by the Master Servicer the related Owner Mortgage Loan File, Retained
Mortgage Loan File, if applicable, and Servicer Mortgage Loan File and shall
execute and deliver such instruments of transfer or assignment, in each case
without recourse, as shall be necessary to vest in the auction purchaser
title to the Mortgage Loan and the Custodian shall have no further
responsibility with regard to such Owner Mortgage Loan File, Retained
Mortgage Loan File, if applicable, or Servicer Mortgage Loan File. None of
the Trustee, the Custodian, the Master Servicer or any Servicer, acting on
behalf of the Trustee, shall provide financing from the Trust Estate to any
purchaser of a Mortgage Loan.

      The Master Servicer, on behalf of the Trustee, shall, pursuant to the
Servicing Agreements, object to the foreclosure upon, or other related
conversion of the ownership of, any Mortgaged Property by the related
Servicer if (i) the Master Servicer believes such Mortgaged Property may be
contaminated with or affected by hazardous wastes or hazardous substances or
(ii) such Servicer does not agree to administer such Mortgaged Property, once
the related Mortgage Loan becomes an REO Mortgage Loan, in a manner which
would not result in a federal tax being imposed upon the Trust Estate or the
REMIC.

      At the direction of the Depositor, the Master Servicer may enter into a
special servicing agreement with an unaffiliated holder of 100% Percentage
Interest of a Class of Class B Certificates or a holder of a class of
securities representing interests in the Class B Certificates and/or other
subordinated mortgage pass-through certificates (such entity, a "Special
Servicer"), such agreement (a "Special Servicing Agreement") to be
substantially in the form of Exhibit M hereto or subject to each Rating
Agency's acknowledgment that the ratings of the Certificates in effect
immediately prior to the entering into of such agreement would not be
qualified, downgraded or withdrawn and the Certificates would not be placed
on credit review status (except for possible upgrading) as a result of such
agreement. Any such agreement may contain provisions whereby such holder may
(a) purchase any Mortgage Loans that are more than 180 days delinquent and
(b) instruct the Master Servicer to instruct a Servicer to the extent
provided in the applicable Servicing Agreement to commence or delay
foreclosure proceedings with respect to delinquent Mortgage Loans and will
contain provisions for the deposit of cash by the holder that would be
available for distribution to Certificateholders if Liquidation Proceeds are
less than they otherwise may have been had the Servicer acted in accordance
with its normal procedures.

      The Master Servicer shall monitor the rating of Wells Fargo & Company
and upon the occurrence of a Document Transfer Event relating to such rating,
shall promptly notify the Depositor, Trustee and Custodian of the occurrence
of such Document Transfer Event.

      Section 3.09 Termination and Substitution of Servicing Agreements.

      Upon the occurrence of any event for which a Servicer may be terminated
pursuant to its Servicing Agreement, the Master Servicer shall promptly
deliver to the Depositor and the Trustee an Officer's Certificate certifying
that an event has occurred which may justify termination of such Servicing
Agreement, describing the circumstances surrounding such event and
recommending what action should be taken by the Trustee with respect to such
Servicer. If the Master Servicer recommends that such Servicing Agreement be
terminated, the Master Servicer's certification must state that the breach is
material and not merely technical in nature. Based upon such certification,
the Master Servicer, or if provided by the applicable Other Servicing
Agreement and upon written direction of the Master Servicer, the Trustee,
shall promptly terminate such Other Servicing Agreement. The Trustee shall
terminate the Wells Fargo Bank Servicing Agreement in accordance with the
provisions of Article 19 thereof. The Master Servicer shall indemnify the
Trustee and hold it harmless from and against any and all claims,
liabilities, costs and expenses (including, without limitation, reasonable
attorneys' fees) arising out of, or assessed against the Trustee in
connection with termination of a Servicing Agreement at the direction of the
Master Servicer except to the extent that such claims, liabilities, costs and
expenses are incurred as a result of the bad faith, willful misfeasance or
gross negligence of the Trustee in the performance of its obligations
hereunder. To the extent that the costs and expenses (including any amounts
paid by the Master Servicer pursuant to the immediately preceding sentence)
of the Master Servicer related to any termination of an Other Servicer,
appointment of a successor servicer to an Other Servicer or the transfer and
assumption of servicing by the Master Servicer with respect to any Other
Servicing Agreement (including, without limitation, (i) all legal costs and
expenses and all due diligence costs and expenses associated with an
evaluation of the potential termination of an Other Servicer as a result of
an event of default by such Other Servicer, (ii) all costs and expenses
associated with the complete transfer of servicing, including all servicing
files and all servicing data and the completion, correction or manipulation
of such servicing data as may be required by the successor servicer to
correct any errors or insufficiencies in the servicing data or otherwise to
enable the successor servicer to service the Mortgage Loans in accordance
with the related Other Servicing Agreement and (iii) any costs incurred by
the Trustee in connection with a servicing transfer) are not fully and timely
reimbursed by the terminated Other Servicer, the Master Servicer shall be
entitled to reimbursement of such costs and expenses from the Certificate
Account. To the extent that the costs and expenses of the Trustee related to
any termination of Wells Fargo Bank, as a Servicer under the Wells Fargo Bank
Servicing Agreement, appointment of a successor to Wells Fargo Bank as a
Servicer or the transfer and assumption of servicing by the Trustee with
respect to the Wells Fargo Bank Servicing Agreement (including, without
limitation, (i) all legal costs and expenses and all due diligence costs and
expenses associated with an evaluation of the potential termination of Wells
Fargo Bank as a Servicer as a result of an event of default by Wells Fargo
Bank as Servicer and (ii) all costs and expenses associated with the complete
transfer of servicing, including all servicing files and all servicing data
and the completion, correction or manipulation of such servicing data as may
be required by the successor servicer to correct any errors or
insufficiencies in the servicing data or otherwise to enable the successor
servicer to service the Mortgage Loans in accordance with the Wells Fargo
Bank Servicing Agreement) are not fully and timely reimbursed by Wells Fargo
Bank as a Servicer, the Trustee shall be entitled to reimbursement of such
costs and expenses from the Certificate Account. If the Master Servicer or
Trustee terminates an Other Servicing Agreement, the Trustee may enter into a
substitute Servicing Agreement with the Master Servicer or, at the Master
Servicer's nomination, with another mortgage loan service company acceptable
to the Trustee, the Master Servicer and each Rating Agency under which the
Master Servicer or such substitute servicer, as the case may be, shall
assume, satisfy, perform and carry out all liabilities, duties,
responsibilities and obligations that are to be, or otherwise were to have
been, satisfied, performed and carried out by such Servicer under such
terminated Servicing Agreement. If the Trustee terminates the Wells Fargo
Bank Servicing Agreement, the Trustee shall enter into a substitute Servicing
Agreement with another mortgage loan service company acceptable to the
Trustee and each Rating Agency under which such substitute servicer shall
assume, satisfy, perform and carry out all liabilities, duties,
responsibilities and obligations that are to be, or otherwise were to have
been, satisfied, performed and carried out by Wells Fargo Bank, in its
capacity as Servicer, under such terminated Servicing Agreement. It is
understood and acknowledged by the parties hereto that there will be a period
of transition not to exceed ninety (90) days before the servicing functions
can be transferred to such substitute servicer. Until such time as the
Trustee enters into a substitute servicing agreement with respect to the
Mortgage Loans previously serviced by an Other Servicer and the transition
period relating to the transfer of such servicing expires, the Master
Servicer shall assume, satisfy, perform and carry out all obligations which
otherwise were to have been satisfied, performed and carried out by an Other
Servicer under its terminated Servicing Agreement. However, in no event shall
the Master Servicer be deemed to have assumed the obligations of a Servicer
to advance payments of principal and interest on a delinquent Mortgage Loan
in excess of the Master Servicer's independent Periodic Advance obligation
under Section 3.03 of this Agreement. As compensation for the Master Servicer
of any servicing obligations fulfilled or assumed by the Master Servicer, the
Master Servicer shall be entitled to any servicing compensation to which a
Servicer would have been entitled if the Servicing Agreement with such
Servicer had not been terminated.

      Section 3.10 Application of Net Liquidation Proceeds.

      For all purposes under this agreement, Net Liquidation Proceeds
received from a Servicer shall be allocated first to accrued and unpaid
interest on the related Mortgage Loan and then to the unpaid principal
balance thereof.

      Section 3.11 Assessment of Servicing Compliance; Registered Public
Accounting Firm Attestation Reports.

      (a) The Master Servicer, at its own expense, shall furnish to the
Depositor, and the Trustee, any Special Servicer (if applicable) and the
Custodian, at their own expense, shall furnish, or otherwise make available,
and shall cause any Servicing Function Participant engaged by any such party
to furnish, and the Master Servicer shall use reasonable effort to cause each
Servicer to furnish with respect to such Servicer and each Servicing Function
Participant engaged by such Servicer and identified to the Master Servicer,
at such party's expense, to the Master Servicer, not later than March 5 of
each year, or if such day is not a Business Day, the next Business Day (with
a 10 day cure period, but in no event later than March 15), commencing in
March 2008, a copy of a report, followed by a hard copy to the Master
Servicer within 10 calendar days, signed by an authorized officer of the
Master Servicer, the Trustee, the Custodian, the Servicing Function
Participant, the Special Servicer (if applicable) or the applicable Servicer,
as applicable, on assessment of compliance with, at a minimum, the Relevant
Servicing Criteria that contains:

      (i) a statement by such party of its responsibility for assessing
   compliance with the Servicing Criteria applicable to it;

      (ii) a statement that such party used the Servicing Criteria applicable
   to it to assess compliance with the Servicing Criteria;

      (iii) such party's assessment of compliance with the Servicing Criteria
   applicable to it as of and for the preceding fiscal year, including, if
   there had been any material instance of noncompliance with the Servicing
   Criteria applicable to it, identifying each such failure and the nature
   and status thereof; and

      (iv) a statement that a registered public accounting firm has issued an
   attestation report on such party's assessment of compliance with the
   Servicing Criteria applicable to it as of and for the preceding fiscal
   year;

provided, however that no such assessment shall be required with respect to
any Servicing Function Participant who would not be considered a separate
"party participating in the servicing function" for purposes of Item 1122 of
Regulation AB, as then interpreted by the Commission. In the event of any
disagreement among any of the parties hereto regarding the application of the
Commission's interpretation to a particular Servicing Function Participant,
the determination of the Master Servicer shall be binding.

      No later than 30 days following the end of each fiscal year, the Master
Servicer shall forward to the Depositor the name of each Servicing Function
Participant engaged by it and what Relevant Servicing Criteria will be
addressed in the report on assessment of compliance prepared by such
Servicing Function Participant. When the Master Servicer submits its
assessments to the Depositor, it will also at such time include the
assessment (and attestation pursuant to Section 3.11(b)) of each Servicing
Function Participant engaged by it.

      No later than 30 days following the end of each fiscal year, each of
the Trustee, any Special Servicer (if applicable) and the Custodian (so long
as the Custodian is not the Master Servicer) shall forward to the Master
Servicer the name of each Servicing Function Participant engaged by it and
what Relevant Servicing Criteria will be addressed in the report on
assessment of compliance prepared by such Servicing Function Participant.
When the Trustee, any Special Servicer (if applicable) and the Custodian (so
long as the Custodian is not the Master Servicer) submit their assessments to
the Master Servicer, each such party will also at such time include the
assessment (and attestation pursuant to Section 3.11(b)) of each Servicing
Function Participant engaged by it.

      The Master Servicer shall confirm that the assessments address the
Relevant Servicing Criteria for each party as set forth on Exhibit R or in
the applicable Servicing Agreement or the applicable Special Servicing
Agreement and shall notify the Depositor of any exceptions and deliver the
assessment of compliance containing such exceptions. Promptly after receipt
of each such report on assessment of compliance, the Depositor shall review
each such report and, if applicable, consult with the Master Servicer, the
Trustee, the Custodian, any Special Servicer (if applicable) and any
Servicing Function Participant as to the nature of any material instance of
noncompliance with the Relevant Servicing Criteria by the Master Servicer,
the Trustee, the Custodian, any Servicer, any Special Servicer (if
applicable), or any Servicing Function Participant engaged by such parties.

      (b) The Master Servicer, at its own expense, shall cause a registered
public accounting firm which is a member of the Institute of Certified Public
Accountants to furnish to the Depositor, and each of the Trustee, the
Custodian and any Special Servicer (if applicable) at their own expense,
shall cause, and shall cause any Servicing Function Participant engaged by
any such party from which an assessment of servicing compliance is required
pursuant to Section 3.11 (a), at such party's expense, to cause, and the
Master Servicer shall use reasonable efforts to cause each Servicer, at such
Servicer's expense, with respect to such Servicer and each Servicing Function
Participant engaged by such Servicer and identified to the Master Servicer,
to cause a registered public accounting firm which is a member of the
Institute of Certified Public Accountants to furnish to the Master Servicer,
not later than March 5 of each year, or if such day is not a Business Day,
the next Business Day (with a 10 calendar day cure period, but in no event
later than March 15), commencing in March 2008, an electronic report (with a
hard copy to follow within 10 calendar days) to the effect that (i) it has
obtained a representation regarding certain matters from the management of
such party, which includes an assertion that such party has complied with the
Relevant Servicing Criteria, and (ii) on the basis of an examination
conducted by such firm in accordance with standards for attestation
engagements issued or adopted by the Public Company Accounting Oversight
Board, it is expressing an opinion as to whether such party's assessment of
compliance with the Relevant Servicing Criteria was fairly stated in all
material respects, or it cannot express an overall opinion regarding such
party's assessment of compliance with the Relevant Servicing Criteria. In the
event that an overall opinion cannot be expressed, such registered public
accounting firm shall state in such report why it was unable to express such
an opinion. Such report must be available for general use and not contain
restricted use language. If requested by the Master Servicer or the
Depositor, such report shall contain or be accompanied by a consent of such
accounting firm to the inclusion or incorporation of such report in the
Depositor's Registration Statement on Form S-3 relating to the Certificates
and the Trust's Form 10-K.

      Promptly after receipt of such report from the Master Servicer, the
Depositor shall review the report and, if applicable, consult with the Master
Servicer if any such report (i) states that the party's assessment of
compliance was not fairly stated in a material respect or (ii) is unable to
state an overall opinion.

      Promptly after receipt of such report from the Trustee, the Custodian,
the applicable Servicer, the Special Servicer (if applicable), or any
Servicing Function Participant engaged by such parties, the Master Servicer
shall review the report and shall promptly notify the Depositor if any such
report (i) states that the party's assessment of compliance was not fairly
stated in a material respect or (ii) is unable to state an overall opinion
and the Depositor shall promptly review each such report and the Depositor
and the Master Servicer shall consult with the parties to which such report
relates.

      The Master Servicer shall make available any report from the Master
Servicer, the Trustee, the Custodian, the applicable Servicer, the Special
Servicer (if applicable), or any Servicing Function Participant furnished
pursuant to Section 3.05 and this Section 3.11, as well as any documents
incorporated by reference into the Prospectus (to the extent such documents
are either in its possession or have been filed with the Commission), to any
Certificateholder requesting such information.

      Section 3.12 Exchange Act Reports.

      (a) Within 15 days after each Distribution Date, the Master Servicer
shall prepare, an authorized officer of the Master Servicer shall sign, and
the Master Servicer shall file with the Commission, on behalf of the Trust,
any Form 10-D required by the Exchange Act, in form and substance as required
by the Exchange Act. The Master Servicer shall file each Form 10-D with a
copy of the related Distribution Date Statement attached thereto. Any
disclosure in addition to the Distribution Date Statement that is required to
be included on Form 10-D ("Additional Form 10-D Disclosure") shall be
reported by the parties set forth on Exhibit S and directed and approved by
the Depositor, and the Master Servicer will have no duty or liability for any
failure hereunder to determine or prepare any Additional Form 10-D Disclosure
(other than with respect to itself) absent such reporting, direction and
approval. If a Form 10-D cannot be filed on time or if a previously filed
Form 10-D needs to be amended, the Master Servicer will follow the procedures
set forth in Section 3.12(d). Promptly (but no later than 1 Business Day)
after filing with the Commission, the Master Servicer will make available on
its internet website a final executed copy of each Form 10-D.

      For so long as the Trust is subject to the Exchange Act reporting
requirements, within five (5) calendar days after the related Distribution Date,
the parties identified on Exhibit S shall (i) provide to the Master Servicer and
the Depositor, to the extent known by a Responsible Officer, in EDGAR-compatible
format, or in such other format as otherwise agreed upon by the Master Servicer
and such party, the form and substance of any Additional Form 10-D Disclosure,
if applicable and (ii) include with such Additional Form 10-D Disclosure, an
Additional Disclosure Notification in the form attached hereto as Exhibit V, and
the Depositor will approve, as to form and substance, or disapprove, as the case
may be, the inclusion of the Additional Form 10-D Disclosure on Form 10-D. The
Master Servicer has no duty under this Agreement to monitor or enforce the
performance by the parties listed on Exhibit S of their duties under this
paragraph or proactively solicit or procure from such parties any Additional
Form 10-D Disclosure; except that the Master Servicer shall enforce the
obligations of the Servicers under the Servicing Agreements. After preparing the
Form 10-D, if the Form 10-D contains any Additional Form 10-D Disclosure, the
Master Servicer shall forward electronically a draft copy of the Form 10-D to
the Depositor for review. Each party to this Agreement acknowledges that the
performance by the Master Servicer of its duties under this Section 3.12(a)
relating to the timely preparation and filing of Form 10-D is contingent upon
such parties strictly observing all applicable deadlines in the performance of
their duties under this Section 3.12(a). The Master Servicer shall have no
liability for any loss, expense, damage or claim arising out of or with respect
to any failure to properly prepare and/or timely file such Form 10-D, where such
failure results from the Master Servicer's inability or failure to receive, on a
timely basis, any information from any other party hereto, any Servicer, the
Custodian or any Special Servicer (if applicable) needed to prepare, arrange for
execution or file such Form 10-D, not resulting from its own negligence, bad
faith or willful misconduct. The Depositor will be responsible for any
reasonable fees assessed and expenses incurred by the Master Servicer in
connection with including any Additional Form 10-D Disclosure on Form 10-D
pursuant to this paragraph.

      (b) Within 90 days after the end of each fiscal year of the Trust or
such earlier date as may be required by the Exchange Act (it being understood
that the fiscal year for the Trust ends on December 31st of each year),
commencing in March 2008, the Master Servicer shall prepare, a senior officer
of the Master Servicer in charge of the master servicing function shall sign,
and the Master Servicer shall file with the Commission, on behalf of the
Trust, a Form 10-K, in form and substance as required by the Exchange Act.
Each such Form 10-K shall include the following items, in each case to the
extent they have been delivered to the Master Servicer within the applicable
timeframes set forth in this Agreement, the related Servicing Agreements, the
Custodial Agreement or, if applicable, the Special Servicing Agreement:

      (i) an annual compliance statement for the Master Servicer, any
   Additional Master Servicer and each Servicer, as described under Section
   3.05;

      (ii) (A) the annual reports on assessment of compliance with servicing
   criteria for the Master Servicer, the Trustee, each Servicer, the
   Custodian, any Special Servicer (if applicable), and each Servicing
   Function Participant, as described under Section 3.11(a), and (B) if any
   party's report on assessment of compliance with Servicing Criteria
   described under Section 3.11(a) identifies any material instance of
   noncompliance, disclosure identifying such instance of noncompliance, or
   if any party's report on assessment of compliance with servicing criteria
   described under Section 3.11(a) is not included as an exhibit to such Form
   10-K, disclosure that such report is not included and an explanation of
   why such report is not included;

      (iii) (A) the registered public accounting firm attestation report for
   each of the Master Servicer, the Trustee, each Servicer, the Custodian,
   any Special Servicer (if applicable), and each Servicing Function
   Participant, as described under Section 3.11(b), and (B) if any registered
   public accounting firm attestation report described under Section 3.11(b)
   identifies any material instance of noncompliance, disclosure identifying
   such instance of noncompliance, or if any such registered public
   accounting firm attestation report is not included as an exhibit to such
   Form 10-K, disclosure that such report is not included and an explanation
   of why such report is not included; and

      (iv) a certification, signed by a senior officer of the Master Servicer
   in charge of the master servicing function, in the form attached hereto as
   Exhibit P or in such other form as may be required by Rules 13a-14 and
   15d-14 under the Exchange Act, as applicable, and any directives or
   interpretations thereof by the Commission (the "Sarbanes-Oxley
   Certification").

      Any disclosure or information in addition to (i) through (iv) above
that is required to be included on Form 10-K ("Additional Form 10-K
Disclosure") shall, pursuant to the paragraph immediately below, be reported
by the parties set forth on Exhibit T and directed and approved by the
Depositor, and the Master Servicer will have no duty or liability for any
failure hereunder to determine or prepare any Additional Form 10-K Disclosure
(other than with respect to itself) absent such reporting, direction and
approval. If a Form 10-K cannot be filed on time or if a previously filed
Form 10-K needs to be amended, the Master Servicer will follow the procedures
set forth in Section 3.12(d). Promptly (but no later than 1 Business Day)
after filing with the Commission, the Master Servicer will make available on
its internet website a final executed copy of each Form 10-K.

      No later than March 5 (with a 10 calendar day cure period, but in no
event later than March 15) of each year that the Trust is subject to the
Exchange Act reporting requirements, commencing in March 2008, (i) the
parties identified on Exhibit T shall provide to the Master Servicer and the
Depositor, to the extent known by a Responsible Officer, in EDGAR-compatible
format, or in such other format as otherwise agreed upon by the Master
Servicer and such party, the form and substance of any Additional Form 10-K
Disclosure, if applicable, and (ii) the parties identified on Exhibit T shall
include with such Additional Form 10-K Disclosure, an Additional Disclosure
Notification in the form attached hereto as Exhibit V, and the Depositor will
approve, as to form and substance, or disapprove, as the case may be, the
inclusion of the Additional Form 10-K Disclosure on Form 10-K. The Master
Servicer has no duty under this Agreement to monitor or enforce the
performance by the parties listed on Exhibit T of their duties under this
paragraph or proactively solicit or procure from such parties any Additional
Form 10-K Disclosure information; except that the Master Servicer shall
enforce the obligations of the Servicers under the Servicing Agreements. The
Depositor will be responsible for any reasonable fees and expenses assessed
or incurred by the Master Servicer in connection with including any
Additional Form 10-K Disclosure on Form 10-K pursuant to this paragraph.

      After preparing the Form 10-K, if the Form 10-K contains any Additional
Form 10-K Disclosure, the Master Servicer shall forward electronically a
draft copy of the Form 10-K to the Depositor for review. Each party to this
Agreement acknowledges that the performance by the Master Servicer of its
duties under this Section 3.12(b) relating to the timely preparation and
filing of Form 10-K is contingent upon such parties strictly observing all
applicable timeframes in the performance of their duties under Sections 3.05,
3.11 or this Section 3.12(b). The Master Servicer shall have no liability for
any loss, expense, damage or claim arising out of or with respect to any
failure to properly prepare and/or timely file such Form 10-K, where such
failure results from the Master Servicer's inability or failure to obtain or
receive, on a timely basis, any information from any other party hereto, any
Servicer, any Special Servicer (if applicable) or the Custodian needed to
prepare, arrange for execution or file such Form 10-K, not resulting from its
own negligence, bad faith or willful misconduct.

      (c) Within four (4) Business Days after the occurrence of an event
requiring disclosure on Form 8-K (each such event, a "Reportable Event"), and
if directed by the Depositor, the Master Servicer shall prepare, an
authorized officer of the Master Servicer shall sign, and the Master Servicer
shall file with the Commission, on behalf of the Trust, any Form 8-K, as
required by the Exchange Act, provided that the Depositor shall prepare and
file the initial Form 8-K in connection with the issuance of the
Certificates. Any disclosure or information related to a Reportable Event or
that is otherwise required to be included on Form 8-K ("Form 8-K Disclosure
Information") shall, pursuant to the paragraph immediately below, be reported
by the parties set forth on Exhibit U and directed and approved by the
Depositor, and the Master Servicer will have no duty or liability for any
failure hereunder to determine or prepare any Form 8-K Disclosure Information
(other than with respect to itself) absent such reporting, direction and
approval. If a Form 8-K cannot be filed on time or if a previously filed Form
8-K needs to be amended, the Master Servicer will follow the procedures set
forth in Section 3.12(d). Promptly (but no later than 1 Business Day) after
filing with the Commission, the Master Servicer will, make available on its
internet website a final executed copy of each Form 8-K.

      For so long as the Trust is subject to the Exchange Act reporting
requirements, no later than the end of business on the second Business Day after
the occurrence of a Reportable Event (i) the parties identified on Exhibit U
shall provide to the Master Servicer and the Depositor, to the extent known by a
Responsible Officer, in EDGAR-compatible form, or in such other form as
otherwise agreed upon by the Master Servicer and such party, the form and
substance of any Form 8-K Disclosure Information, if applicable, and (ii) the
parties identified on Exhibit U shall include with such Additional Form 8-K
Disclosure, an Additional Disclosure Notification in the form attached hereto as
Exhibit V and the Depositor will approve, as to form and substance, or
disapprove, as the case may be, the inclusion of the Form 8-K Disclosure
Information on Form 8-K. The Master Servicer has no duty under this Agreement to
monitor or enforce the performance by the parties listed on Exhibit U of their
duties under this paragraph or proactively solicit or procure from such parties
any Form 8-K Disclosure Information; except that the Master Servicer shall
enforce the obligations of the Servicers under the Servicing Agreements. The
Depositor will be responsible for any reasonable fees and expenses assessed or
incurred by the Master Servicer in connection with including any Form 8-K
Disclosure Information on Form 8-K pursuant to this paragraph.

      After preparing the Form 8-K, the Master Servicer shall forward
electronically a draft copy of the Form 8-K to the Depositor for review. Each
party to this Agreement acknowledges that the performance by the Master Servicer
of its duties under this Section 3.12(c) relating to the timely preparation and
filing of Form 8-K is contingent upon such party strictly observing all
applicable timeframes in the performance of its duties under this Section
3.12(c). The Master Servicer shall have no liability for any loss, expense,
damage or claim arising out of or with respect to any failure to properly
prepare and/or timely file such Form 8-K, where such failure results from the
Master Servicer's inability or failure to obtain or receive, on a timely basis,
any information from any other party hereto, any Servicer, the Custodian or any
Special Servicer (if applicable) needed to prepare, arrange for execution or
file such Form 8-K, not resulting from its own negligence, bad faith or willful
misconduct.

      (d) In the event that the Master Servicer is unable to timely file with
the Commission all or any required portion of any Form 8-K, 10-D or 10-K
required to be filed by this Agreement because required disclosure
information was either not delivered to it or delivered to it after the
delivery deadlines set forth in this Agreement or for any other reason, the
Master Servicer will promptly notify the Depositor and, in the case of Form
10-D or 10-K, the Master Servicer will prepare, sign and file a Form 12b-25
pursuant to Rule 12b-25 of the Exchange Act not later than the Business Day
following the due date of the applicable report. Within five days following
the due date of any Form 10-D as to which it has filed a Form 12b-25, the
Master Servicer shall prepare, sign and file the related Form 10-D. Within 15
days following the due date of any Form 10-K as to which it has filed a Form
12b-25, the Master Servicer shall prepare, sign and file the related Form
10-K. In the case of Form 8-K, the Master Servicer will, upon receipt of all
required Form 8-K Disclosure Information and at the direction of the
Depositor, include such disclosure information on the next Form 10-D. In the
event that any previously filed Form 8-K, 10-D or 10-K needs to be amended,
the Master Servicer will notify the Depositor and each party whose
cooperation is required in connection with the preparation of such amendment;
provided however that such notice shall not be required in connection with an
amendment to Form 10-D due to a revision made to any Distribution Date
Statement. Any amendment to any previously filed Form 8-K, 10-D or 10-K shall
be prepared, signed and filed by the Master Servicer. The parties to this
Agreement acknowledge that the performance by the Master Servicer of its
duties under this Section 3.12(d) related to the timely preparation and
filing of a Form 12b-25 or any amendment to Form 8-K, 10-D or 10-K is
contingent upon each such party performing its duties under this Section. The
Master Servicer shall have no liability for any loss, expense, damage or
claim arising out of or with respect to any failure to properly prepare
and/or timely file any such Form 12b-25 or any amendments to Forms 8-K, 10-D
or 10-K, where such failure results from the Master Servicer's inability or
failure to obtain or receive, on a timely basis, any information from any
other party hereto, any Servicer, the Custodian or any Special Servicer (if
applicable) needed to prepare, arrange for execution or file such Form 12b-25
or any amendments to Form 8-K, 10-D or 10-K, not resulting from its own
negligence, bad faith or willful misconduct.

      (e) Unless otherwise instructed by the Depositor, on or prior to
January 30 of the first year in which the Master Servicer is able to do so
under applicable law, the Master Servicer shall prepare, an authorized
officer of the Master Servicer shall sign, and the Master Servicer shall file
with the Commission, on behalf of the Trust, a Form 15 relating to the
automatic suspension of reporting in respect of the Trust under the Exchange
Act. At the beginning of any year after the filing of a Form 15, if the
number of Certificateholders of record exceeds the number set forth in
Section 15(d) of the Exchange Act or the regulations promulgated pursuant
thereto which would cause the Trust to again become subject to the reporting
requirements of the Exchange Act, the Master Servicer shall recommence
preparing and filing reports on Forms 10-D, 10-K and 8-K as required pursuant
to this Section.

      (f) To the extent the Master Servicer is obligated to give any notice
to the Depositor pursuant to this Section 3.12, such notice may,
notwithstanding the provisions of Section 10.05 of this Agreement, be
delivered via facsimile to 240-586-5983 or via electronic mail to
Structuredfinance-frederick@wellsfargo.com.

                                   ARTICLE IV

                    DISTRIBUTIONS IN RESPECT OF CERTIFICATES;
                         PAYMENTS TO CERTIFICATEHOLDERS;
                             STATEMENTS AND REPORTS

      Section 4.01 Distributions.

      (a)  Amounts allocated to a Class of Exchangeable REMIC Certificates
pursuant to this Section 4.01(a) will be calculated assuming no exchanges
have ever occurred. Exchangeable Certificates will receive distributions in
accordance with Section 4.01(g) and will not be allocated amounts under this
Section 4.01(a). On each Distribution Date, the Pool Distribution Amount will
be applied in the following amounts, to the extent the Pool Distribution
Amount is sufficient therefor, in the manner and in the order of priority as
follows:

      first, to the Classes of Class A Certificates, pro rata, based upon
their respective Interest Accrual Amounts, in an aggregate amount up to the
Class A Interest Accrual Amount with respect to such Distribution Date;

      second, to the Classes of Class A Certificates, pro rata, based upon
their respective Class A Unpaid Interest Shortfalls in an aggregate amount up
to the Aggregate Class A Unpaid Interest Shortfall;

      third, concurrently, to the Class A Non-PO Certificates and the Class
A-PO Certificates, pro rata, based on their respective Class A Non-PO Optimal
Principal Amount and Class A-PO Optimal Principal Amount, (1) to the Classes
of Class A Non-PO Certificates, in an aggregate amount up to the Class A
Non-PO Optimal Principal Amount, such distribution to be allocated among such
Classes in accordance with Section 4.01(b) or Section 4.01(c), as applicable,
and (2) to the Class A-PO Certificates in an amount up to the Class A-PO
Optimal Principal Amount;

      fourth, to the Class A-PO Certificates in an amount up to the Class
A-PO Deferred Amount from amounts otherwise distributable (without regard to
this Paragraph fourth) first to the Class B-6 Certificates pursuant to
Paragraph twenty-second, below, second to the Class B-5 Certificates pursuant
to Paragraph nineteenth, below, third to the Class B-4 Certificates pursuant
to Paragraph sixteenth, below, fourth to the Class B-3 Certificates pursuant
to Paragraph thirteenth, below, fifth to the Class B-2 Certificates pursuant
to Paragraph tenth below, and sixth to the Class B-1 Certificates pursuant to
Paragraph seventh below;

      fifth, to the Class B-1 Certificates in an amount up to the Interest
Accrual Amount for the Class B-1 Certificates with respect to such
Distribution Date;

      sixth, to the Class B-1 Certificates in an amount up to the Class B-1
Unpaid Interest Shortfall;

      seventh, to the Class B-1 Certificates in an amount up to the Class B-1
Optimal Principal Amount; provided, however, that the amount distributable to
the Class B-1 Certificates pursuant to this Paragraph seventh will be reduced
by the amount, if any, that would have been distributable to the Class B-1
Certificates hereunder used to pay the Class A-PO Deferred Amount as provided
in Paragraph fourth above;

      eighth, to the Class B-2 Certificates in an amount up to the Interest
Accrual Amount for the Class B-2 Certificates with respect to such
Distribution Date;

      ninth, to the Class B-2 Certificates in an amount up to the Class B-2
Unpaid Interest Shortfall;

      tenth, to the Class B-2 Certificates in an amount up to the Class B-2
Optimal Principal Amount; provided, however, that the amount distributable to
the Class B-2 Certificates pursuant to this Paragraph tenth will be reduced
by the amount, if any, that would have been distributable to the Class B-2
Certificates hereunder used to pay the Class A-PO Deferred Amount as provided
in Paragraph fourth above;

      eleventh, to the Class B-3 Certificates in an amount up to the Interest
Accrual Amount for the Class B-3 Certificates with respect to such
Distribution Date;

      twelfth, to the Class B-3 Certificates in an amount up to the Class B-3
Unpaid Interest Shortfall;

      thirteenth, to the Class B-3 Certificates in an amount up to the Class
B-3 Optimal Principal Amount; provided, however, that the amount
distributable to the Class B-3 Certificates pursuant to this Paragraph
thirteenth will be reduced by the amount, if any, that would have been
distributable to the Class B-3 Certificates hereunder used to pay the Class
A-PO Deferred Amount as provided in Paragraph fourth above;

      fourteenth, to the Class B-4 Certificates in an amount up to the
Interest Accrual Amount for the Class B-4 Certificates with respect to such
Distribution Date;

      fifteenth, to the Class B-4 Certificates in an amount up to the Class
B-4 Unpaid Interest Shortfall;

      sixteenth, to the Class B-4 Certificates in an amount up to the Class
B-4 Optimal Principal Amount; provided, however, that the amount
distributable to the Class B-4 Certificates pursuant to this Paragraph
sixteenth will be reduced by the amount, if any, that would have been
distributable to the Class B-4 Certificates hereunder used to pay the Class
A-PO Deferred Amount as provided in Paragraph fourth above;

      seventeenth, to the Class B-5 Certificates in an amount up to the
Interest Accrual Amount for the Class B-5 Certificates with respect to such
Distribution Date;

      eighteenth, to the Class B-5 Certificates in an amount up to the Class
B-5 Unpaid Interest Shortfall;

      nineteenth, to the Class B-5 Certificates in an amount up to the Class
B-5 Optimal Principal Amount; provided, however, that the amount
distributable to the Class B-5 Certificates pursuant to this Paragraph
nineteenth will be reduced by the amount, if any, that would have been
distributable to the Class B-5 Certificates hereunder used to pay the Class
A-PO Deferred Amount as provided in Paragraph fourth above;

      twentieth, to the Class B-6 Certificates in an amount up to the
Interest Accrual Amount for the Class B-6 Certificates with respect to such
Distribution Date;

      twenty-first, to the Class B-6 Certificates in an amount up to the
Class B-6 Unpaid Interest Shortfall;

      twenty-second, to the Class B-6 Certificates in an amount up to the
Class B-6 Optimal Principal Amount; provided, however, that the amount
distributable to the Class B-6 Certificates pursuant to this Paragraph
twenty-second will be reduced by the amount, if any, that would have been
distributable to the Class B-6 Certificates hereunder used to pay the Class
A-PO Deferred Amount as provided in Paragraph fourth above; and

      twenty-third, to the Holder of the Class A-R Certificate, any amounts
remaining in the Payment Account.

      Notwithstanding the foregoing, after the Principal Balance of any Class
has been reduced to zero, such Class will be entitled to no further
distributions of principal or interest (including, without limitation, any
Unpaid Interest Shortfalls).

      With respect to any Distribution Date, the amount of the Principal
Adjustment, if any, attributable to any Class of Class B Certificates will be
allocated to the Classes of Class A Non-PO Certificates and any Class of
Class B Certificates with a lower numerical designation pro rata based on
their outstanding Principal Balances.

      On each Distribution Date, any Reimbursement Amount shall be allocated
sequentially to the Classes of Certificates (other than Exchangeable
Certificates) then outstanding which bore the loss to which such
Reimbursement Amount relates beginning with the most senior of such Class of
Certificates, up to, with respect to each Class, the amount of loss borne by
such Class. Any amount allocated to a Class shall be distributed to such
Class subject to Section 4.01(g). Any Reimbursement Amount remaining after
the application described in the preceding sentence shall be included in the
Pool Distribution Amount.

      (b) The allocation of the Class A Non-PO Distribution Amount to a Class
of Exchangeable REMIC Certificates will be made assuming no exchanges have
ever occurred. Amounts distributable to Exchangeable Certificates will be
made as described in Section 4.01(g). On each Distribution Date occurring
prior to the Subordination Depletion Date, the Class A Non-PO Principal
Distribution Amount will be allocated among and distributed in reduction of
the Principal Balances of the Class A Non-PO Certificates, sequentially, as
follows:

   first, to the Class A-R Certificate; and

   second, concurrently, to the Class A-2 and Class A-3 Certificates, pro rata.

      (c) Notwithstanding the foregoing, on each Distribution Date occurring
on or subsequent to the Subordination Depletion Date, the Class A Non-PO
Principal Distribution Amount shall be distributed among the Classes of Class
A Non-PO Certificates, pro rata, in accordance with their outstanding
Principal Balances without regard to either the proportions or the priorities
set forth in Section 4.01(b).

      (d) (i) For purposes of determining whether the Classes of Class B
Certificates are eligible to receive distributions of principal with respect
to any Distribution Date, the following tests shall apply:

      (A) if the Current Class B-1 Fractional Interest is less than the
   Original Class B-1 Fractional Interest and the Class B-1 Principal Balance
   is greater than zero, the Class B-2, Class B-3, Class B-4, Class B-5 and
   Class B-6 Certificates shall not be eligible to receive distributions of
   principal; or

      (B) if the Current Class B-2 Fractional Interest is less than the
   Original Class B-2 Fractional Interest and the Class B-2 Principal Balance
   is greater than zero, the Class B-3, Class B-4, Class B-5 and Class B-6
   Certificates shall not be eligible to receive distributions of principal;
   or

      (C) if the Current Class B-3 Fractional Interest is less than the
   Original Class B-3 Fractional Interest and the Class B-3 Principal Balance
   is greater than zero, the Class B-4, Class B-5 and Class B-6 Certificates
   shall not be eligible to receive distributions of principal; or

      (D) if the Current Class B-4 Fractional Interest is less than the
   Original Class B-4 Fractional Interest and the Class B-4 Principal Balance
   is greater than zero, the Class B-5 and Class B-6 Certificates shall not
   be eligible to receive distributions of principal; or

      (E) if the Current Class B-5 Fractional Interest is less than the
   Original Class B-5 Fractional Interest and the Class B-5 Principal Balance
   is greater than zero, the Class B-6 Certificates shall not be eligible to
   receive distributions of principal.

      (ii) Notwithstanding the foregoing, if on any Distribution Date the
aggregate distributions to Holders of the Classes of Class B Certificates
entitled to receive distributions of principal would reduce the Principal
Balances of the Classes of Class B Certificates entitled to receive
distributions of principal below zero, first the Class B Prepayment
Percentage of any affected Class of Class B Certificates for such
Distribution Date beginning with the affected Class with the lowest numerical
Class designation and then, if necessary, the Class B Percentage of such
Class of the Class B Certificates for such Distribution Date shall be reduced
to the respective percentages necessary to bring the Principal Balance of
such Class of Class B Certificates to zero. The Class B Prepayment
Percentages and the Class B Percentages of the remaining Classes of Class B
Certificates will be recomputed substituting for the Subordinated Prepayment
Percentage and Subordinated Percentage in such computations the difference
between (A) the Subordinated Prepayment Percentage or Subordinated
Percentage, as the case may be, and (B) the percentages determined in
accordance with the preceding sentence necessary to bring the Principal
Balances of the affected Classes of Class B Certificates to zero; provided,
however, that if the Principal Balances of all the Classes of Class B
Certificates eligible to receive distributions of principal shall be reduced
to zero on such Distribution Date, the Class B Prepayment Percentage and
Class B Percentage of the Class of Class B Certificates with the lowest
numerical Class designation which would otherwise be ineligible to receive
distributions of principal in accordance with this Section shall equal the
remainder of the Subordinated Prepayment Percentage for such Distribution
Date minus the sum of the Class B Prepayment Percentages of the Classes of
Class B Certificates having lower numerical Class designations, if any, and
the remainder of the Subordinated Percentage for such Distribution Date minus
the sum of the Class B Percentages of the Classes of Class B Certificates
having lower numerical Class designations, if any, respectively. Any
entitlement of any Class of Class B Certificates to principal payments solely
pursuant to this clause (ii) shall not cause such Class to be regarded as
being eligible to receive principal distributions for the purpose of applying
the definition of its Class B Percentage or Class B Prepayment Percentage.

      (e) On each Distribution Date other than the Final Distribution Date
(if such Final Distribution Date is in connection with a purchase of the
assets of the Trust Estate by the Depositor), the Paying Agent shall, from
funds remitted to it by the Master Servicer, distribute to each
Certificateholder of record on the preceding Record Date (other than as
provided in Section 9.01 respecting the final distribution to
Certificateholders or in the last paragraph of this Section 4.01(e)
respecting the final distribution in respect of any Class) either in
immediately available funds by wire transfer to the account of such
Certificateholder at a bank or other entity having appropriate facilities
therefor, if such Certificateholder has so notified the Paying Agent at least
seven Business Days prior to the Distribution Date or if such Holder has not
so notified the Paying Agent, by check mailed to such Holder at the address
of such Holder appearing in the Certificate Register, such Holder's share of
the Class A Distribution Amount with respect to each Class of Class A
Certificates and the Class B Distribution Amount with respect to each Class
of Class B Certificates.

      In the event that, on any Distribution Date prior to the Final
Distribution Date, the Principal Balance of any Class of Class A Certificates
(other than the Residual Certificate) or the Principal Balance of any Class
of Class B Certificates would be reduced to zero, or, in the case of a Class
of Exchangeable Certificates, the Principal Balances of the Related
Exchangeable REMIC Certificates, would be reduced to zero, the Master
Servicer shall, as soon as practicable after the Determination Date relating
to such Distribution Date, send notice to the Paying Agent. The Paying Agent
shall then send a notice to each Certificateholder of such Class with a copy
to the Certificate Registrar, specifying that the final distribution with
respect to such Class will be made on such Distribution Date only upon the
presentation and surrender of such Certificateholder's Certificates at the
office or agency of the Certificate Registrar therein specified; provided,
however, that the failure to give such notice will not entitle a
Certificateholder to any interest beyond the interest payable with respect to
such Distribution Date in accordance with Section 4.01(a).

      (f) The Paying Agent shall withhold or cause to be withheld such
amounts as may be required by the Code (giving full effect to any exemptions
from withholding and related certifications required to be furnished by
Certificateholders and any reductions to withholding by virtue of any
bilateral tax treaties and any applicable certification required to be
furnished by Certificateholders with respect thereto) from distributions to
be made to Persons other than U.S. Persons ("Non-U.S. Persons"). Amounts
withheld pursuant to this Section 4.01(f) shall be treated as having been
distributed to the related Certificateholder for all purposes of this
Agreement. For the purposes of this paragraph, a "U.S. Person" is a citizen
or resident of the United States, a corporation or partnership (unless, in
the case of a partnership, Treasury regulations are adopted that provide
otherwise) created or organized in or under the laws of the United States,
any state thereof or the District of Columbia, including an entity treated as
a corporation or partnership for federal income tax purposes, an estate whose
income is subject to United States federal income tax regardless of its
source, or a trust if a court within the United States is able to exercise
primary supervision over the administration of such trust, and one or more
such U.S. Persons have the authority to control all substantial decisions of
such trust (or, to the extent provided in applicable Treasury regulations,
certain trusts in existence on August 20, 1996 which are eligible to elect to
be treated as U.S. Persons).

      (g) (i) An Exchangeable Combination consisting of Outstanding
Exchangeable Certificates will receive its proportionate share of
distributions in respect of interest allocated to the Related Exchangeable
REMIC Certificates pursuant to Section 4.01(a) and Section 9.01. Such amount
of interest will then be distributed to the Class of Exchangeable
Certificates within such Exchangeable Combination.

      (ii) An Exchangeable Combination consisting of Outstanding Exchangeable
Certificates will receive its proportionate share of distributions in respect
of principal allocated to the Related Exchangeable REMIC Certificates
pursuant to Sections 4.01(b) and (c) and Section 9.01. Such amount of
principal will then be distributed in respect of such Exchangeable
Combination to the Class of Exchangeable Certificates within such
Exchangeable Combination.

      (iii) An Exchangeable Combination consisting of Outstanding
Exchangeable Certificates will receive its proportionate share of any
Principal Adjustment or Reimbursement Amount allocated to the Related
Exchangeable REMIC Certificates. Any such Principal Adjustment or
Reimbursement Amount will then be allocated to the Class of Outstanding
Exchangeable Certificates included in such Exchangeable Combination.

      Section 4.02 Allocation of Realized Losses.

      (a) With respect to any Distribution Date, the principal portion of any
Realized Loss (other than Debt Service Reductions) will be allocated as
follows:

      first, concurrently, to the Class A-PO Certificates and Class B-6
Certificates, pro rata, based on the applicable PO Fraction and the
applicable Non-PO Fraction of such Mortgage Loans, respectively, until the
Class B-6 Principal Balance has been reduced to zero;

      second, concurrently, to the Class A-PO Certificates and Class B-5
Certificates, pro rata, based on the applicable PO Fraction and the
applicable Non-PO Fraction of such Mortgage Loans, respectively, until the
Class B-5 Principal Balance has been reduced to zero;

      third, concurrently, to the Class A-PO Certificates and Class B-4
Certificates, pro rata, based on the applicable PO Fraction and the
applicable Non-PO Fraction of such Mortgage Loans, respectively, until the
Class B-4 Principal Balance has been reduced to zero;

      fourth, concurrently, to the Class A-PO Certificates and Class B-3
Certificates, pro rata, based on the applicable PO Fraction and the
applicable Non-PO Fraction of such Mortgage Loans, respectively, until the
Class B-3 Principal Balance has been reduced to zero;

      fifth, concurrently, to the Class A-PO Certificates and Class B-2
Certificates, pro rata, based on the applicable PO Fraction and the
applicable Non-PO Fraction of such Mortgage Loans, respectively, until the
Class B-2 Principal Balance has been reduced to zero;

      sixth, concurrently, to the Class A-PO Certificates and Class B-1
Certificates, pro rata, based on the applicable PO Fraction and the
applicable Non-PO Fraction of such Mortgage Loans, respectively, until the
Class B-1 Principal Balance has been reduced to zero; and

      seventh, concurrently, to the Class A Non-PO Certificates and Class
A-PO Certificates, pro rata, based on the applicable Non-PO Fraction and the
applicable PO Fraction of such Mortgage Loans, respectively.

      This allocation of Realized Losses will be effected through the
reduction of the applicable Class's Principal Balance through the operation
of the definitions of Principal Balance, Class B-1 Principal Balance, Class
B-2 Principal Balance, Class B-3 Principal Balance, Class B-4 Principal
Balance, Class B-5 Principal Balance and Class B-6 Principal Balance.

      A Class of Outstanding Exchangeable Certificates will be allocated its
proportionate share (based on Maximum Principal Balance) of (i) any decrease
in the Principal Balance of the Class or Classes of Related Exchangeable
REMIC Certificates as a result of the application of the third or fourth
sentences of the definition of Principal Balance or (ii) any increase in the
Principal Balance of the Class or Classes of Related Exchangeable REMIC
Certificates as a result of the application of the third or fifth sentences
of the definition of Principal Balance.

      (b) Any Realized Losses allocated to a Class of Class A Certificates or
Class B Certificates pursuant to Section 4.02(a) shall be allocated among the
Certificates of such Class based on their Percentage Interests.

      (c) After the Class B Principal Balance has been reduced to zero, the
interest portion of Realized Losses will be allocated among the outstanding
Classes of Class A Certificates based upon their Class A Interest Percentages.

      (d) Realized Losses allocated in accordance with this Section 4.02 will
be allocated as follows: (i) Liquidated Loan Losses on Liquidated Loans for
which the Liquidation Proceeds were received during, and Bankruptcy Losses
incurred in a period corresponding to, an Unscheduled Principal Receipt
Period for Full Unscheduled Principal Receipts that is a Mid-Month Receipt
Period will be allocated on the Determination Date in the month following the
month in which such Mid-Month Receipt Period ended and (ii) Liquidated Loan
Losses on Liquidated Loans for which the Liquidation Proceeds were received
during, and Bankruptcy Losses incurred in a period corresponding to, an
Unscheduled Principal Receipt Period for Full Unscheduled Principal Receipts
that is a Prior Month Receipt Period will be allocated on the Determination
Date in the second month following the month which is such Prior Month
Receipt Period.

      Section 4.03 Paying Agent.

      (a) The Paying Agent shall establish and maintain a Payment Account,
which shall be a separate trust account (unless the Master Servicer is the
Paying Agent, in which case, the Certificate Account may be the Payment
Account) and an Eligible Account, in which the Master Servicer shall cause to
be deposited from funds in the Certificate Account or, to the extent required
hereunder, from its own funds (i) at or before 10:00 a.m., New York time, on
the Business Day preceding each Distribution Date, by wire transfer of
immediately available funds, any Periodic Advance for such Distribution Date,
pursuant to Section 3.03 and (ii) at or before 10:00 a.m., New York time, on
the Business Day preceding each Distribution Date, by wire transfer of
immediately available funds, an amount equal to the Pool Distribution Amount.
The Master Servicer may cause the Paying Agent to invest the funds in the
Payment Account. Any such investment shall be in Eligible Investments, which
shall mature not later than the Business Day preceding the related
Distribution Date (unless the Eligible Investments are obligations of the
institution that maintains such account, in which case such Eligible
Investments shall mature not later than the Distribution Date), and shall not
be sold or disposed of prior to maturity. All income and gain realized from
any such investment shall be for the benefit of the Master Servicer and shall
be subject to its withdrawal or order from time to time. The amount of any
losses incurred in respect of any such investments shall be deposited in the
Payment Account by the Master Servicer out of its own funds immediately as
realized. The Paying Agent may withdraw from the Payment Account any amount
deposited in the Payment Account that was not required to be deposited
therein and may clear and terminate the Payment Account pursuant to Section
9.01.

      (b) Wells Fargo Bank is hereby appointed as initial Paying Agent to
make distributions to Certificateholders and to make available to
Certificateholders the Distribution Date Statements and the annual statements
required by Section 4.04. The Trustee may, at any time, remove or replace the
Paying Agent, other than Wells Fargo Bank for so long as Wells Fargo Bank is
acting as the Master Servicer. If Wells Fargo Bank is no longer acting as
Master Servicer, the Master Servicer shall pay, from its own funds, the
reasonable compensation of any Paying Agent other than Wells Fargo Bank.

      The Trustee shall cause any Paying Agent that is not HSBC Bank USA,
National Association or Wells Fargo Bank to execute and deliver to the
Trustee an instrument (a "Paying Agent Agreement") in which such Paying Agent
agrees with the Trustee that such Paying Agent shall:

      (i) hold all amounts remitted to it by the Master Servicer for
   distribution to Certificateholders in trust for the benefit of
   Certificateholders until such amounts are distributed to
   Certificateholders or otherwise disposed of as herein provided;

      (ii) give the Trustee notice of any default by the Master Servicer in
   remitting any required amount;

      (iii) at any time during the continuance of any such default, upon the
   written request of the Trustee, forthwith pay to the Trustee all amounts
   held in trust by such Paying Agent; and

      (iv) if the Depositor or the Master Servicer determines it necessary in
   order to comply with the requirements of Regulation AB, provide to the
   Master Servicer the assessment of compliance and accountants report
   provided for in Section 3.11 with respect to the Servicing Criteria set
   forth in Item 1122(d) of Regulation AB applicable to the duties of the
   Paying Agent.

      Section 4.04 Statements to Certificateholders; Reports to the Trustee
and the Depositor.

      (a) On each Distribution Date, the Master Servicer shall make available
in accordance with subsection (b) of this Section 4.04 to each Holder of a
Certificate, the Trustee, the Paying Agent and the Depositor a statement (the
"Distribution Date Statement") setting forth:

      (i) the applicable Determination Date, the applicable Record Date and the
   actual Distribution Date;

      (ii) the amount of such distribution to Holders of each Class of Class A
   Certificates allocable to principal, assuming, in the case of a Class of
   Exchangeable REMIC Certificates, that no exchanges have occurred and, in the
   case of a Class of Exchangeable Certificates, that all exchanges have
   occurred, separately identifying the aggregate amount of any Unscheduled
   Principal Receipts and Liquidation Proceeds included therein and the
   Principal Balance of each Class of Class A Certificates (other than a Class
   of Exchangeable Certificates) and the Maximum Principal Balance of each Class
   of Exchangeable Certificates;

      (iii) (A) the amount of such distribution to Holders of each Class of
   Class A Certificates allocable to interest, assuming, in the case of a Class
   of Exchangeable REMIC Certificates, that no exchanges have occurred and, in
   the case of a Class of Exchangeable Certificates, that all exchanges have
   occurred, (B) the amount of the Current Class A Interest Distribution Amount
   allocated to each Class of Class A Certificates, (C) any Interest Shortfall
   Amounts arising with respect to such Distribution Date and any remaining
   Class A Unpaid Interest Shortfall with respect to each Class after giving
   effect to such distribution, (D) the amount of any Non-Supported Interest
   Shortfalls allocated to each Class of Class A Certificates for such
   Distribution Date, (E) the amount of any Relief Act Shortfall allocated to
   each Class of Class A Certificates for such Distribution Date and (F) for
   each Class of Exchangeable Certificates, comparable information to that
   required in clauses (B), (C), (D) and (E) assuming all exchanges have
   occurred based on such Class' proportionate share of such amounts allocated
   to the Related Exchangeable REMIC Certificates;

      (iv) the amount of such distribution to Holders of each Class of Class B
   Certificates allocable to principal, separately identifying the aggregate
   amount of any Unscheduled Principal Receipts and Liquidation Proceeds
   included therein and the Principal Balance of each Class of Class B
   Certificates;

      (v) (A) the amount of such distribution to Holders of each Class of Class
   B Certificates allocable to interest, (B) the amount of the Current Class B
   Interest Distribution Amount allocated to each Class of Class B Certificates,
   (C) any Class B Interest Shortfall Amounts arising with respect to such
   Distribution Date and any remaining Class B Unpaid Interest Shortfall with
   respect to each Class of Class B Certificates after giving effect to such
   distribution, (D) the amount of any Non-Supported Interest Shortfall
   allocated to each Class of Class B Certificates for such Distribution Date
   and (E) the amount of any Relief Act Shortfall allocated to each Class of
   Class B Certificates for such Distribution Date;

      (vi) the amount of any Periodic Advance by or reimbursed to any Servicer,
   the Master Servicer or the Trustee pursuant to the Servicing Agreements or
   this Agreement;

      (vii) the number and aggregate principal balance of Mortgage Loans
   outstanding, the weighted average Mortgage Interest Rate and weighted average
   remaining term to maturity of the Mortgage Loans outstanding and the
   cumulative prepayment amounts, in each case, as of the preceding
   Determination Date;

      (viii) the number and aggregate principal balances of the Mortgage Loans
   by range of current Mortgage Interest Rates;

      (ix) the pool factors for such Distribution Date;

      (x) the beginning and ending balance of the Certificate Account;

      (xi) the Class A Principal Balance, the Principal Balance of each Class of
   Class A Certificates (other than a Class of Exchangeable Certificates), the
   Maximum Principal Balance of each Class of Exchangeable Certificates, the
   Class B Principal Balance and the Principal Balance of each Class of Class B
   Certificates prior to and after giving effect to the distributions of
   principal made, and the principal portion of Realized Losses, if any,
   allocated with respect to such Distribution Date;

      (xii) the Adjusted Pool Amount, the Adjusted Pool Amount (Non-PO Portion),
   the Adjusted Pool Amount (PO Portion), the Pool Scheduled Principal Balance
   of the Mortgage Loans for such Distribution Date, the aggregate Scheduled
   Principal Balance of the Discount Mortgage Loans for such Distribution Date;

      (xiii) the aggregate Scheduled Principal Balances of the Mortgage Loans
   serviced by Wells Fargo Bank in its capacity as Servicer and, collectively,
   by the Other Servicers as of such Distribution Date;

      (xiv) the Class A Percentage for such Distribution Date;

      (xv) the Class A Prepayment Percentage for such Distribution Date;

      (xvi) the Class B-1, Class B-2, Class B-3, Class B-4, Class B-5 and Class
   B-6 Percentages for such Distribution Date;

      (xvii) the Class B-1, Class B-2, Class B-3, Class B-4, Class B-5 and Class
   B-6 Prepayment Percentages for such Distribution Date;

      (xviii) the number and aggregate principal balances of the Mortgage Loans
   (A) delinquent (exclusive of Mortgage Loans in foreclosure or bankruptcy),
   grouping such delinquent Mortgage Loans in 30 day increments, up to 180 days
   delinquent (determined in accordance with the Mortgage Bankers' Association
   delinquency methodology), (B) in foreclosure, as of the close of business on
   the last day of the calendar month preceding the Distribution Date and (C) in
   bankruptcy as of the close of business on the last day of the calendar month
   preceding the Distribution Date;

      (xix) the number and aggregate principal balances of the Mortgage Loans
   that are REO Mortgage Loans as of the Determination Date immediately
   preceding such Distribution Date;

      (xx) the aggregate amount of Realized Losses incurred during the preceding
   calendar month;

      (xxi) any expenses or indemnification amounts paid by the Trust, the
   specific purpose of each payment and the parties to whom the payments were
   made;

      (xxii) the amount by which the Principal Balance of each Class of Class B
   Certificates has been reduced as a result of Realized Losses allocated as of
   such Distribution Date;

      (xxiii) the amount of the aggregate Servicing Fees and Master Servicing
   Fees paid (and not previously reported) with respect to the related
   Distribution Date and the amount by which the aggregate Available Master
   Servicer Compensation has been reduced by the Prepayment Interest Shortfall
   for the related Distribution Date;

      (xxiv) the amount of PMI Advances made by a Servicer, if any;

      (xxv) the Class A Pass-Through Rate for each Class of Class A Certificates
   and the Class B Pass-Through Rate for each Class of Class B Certificates;

      (xxvi) the Class A-PO Deferred Amount, if any;

      (xxvii) any material modifications, extensions or waivers to Mortgage Loan
   terms, fees, penalties or payments since the previous Distribution Date;

      (xxviii) any material breaches of representations and warranties relating
   to the Mortgage Loans or material breaches of transaction covenants;

      (xxix) with respect to any Mortgage Loan as to which there has been a
   Servicer Modification during the calendar month preceding such Distribution
   Date, the Scheduled Principal Balance as of such Distribution Date, the
   Monthly Payment prior to such modification and the Monthly Payment after such
   modification;

      (xxx) if any of the Mortgage Loans have prepayment penalties, the
   aggregate amount of any prepayment penalties paid;

      (xxxi) a statement as to whether any exchanges of Exchangeable REMIC
   Certificates or Exchangeable Certificates have taken place since the
   preceding Distribution Date, and, if applicable, the names, Principal
   Balances, Maximum Principal Balances, Pass-Through Rates and any interest and
   principal paid, including any shortfalls allocated, of any Classes of
   Exchangeable REMIC Certificates or Exchangeable Certificates that were
   received by the Certificateholder as a result of such exchange; and

      (xxxii) any other customary information as is required to enable
   Certificateholders to prepare their tax returns.

      In the case of information furnished with respect to a Class of Class A
Certificates pursuant to clauses (ii) and (iii) above and with respect to a
Class of Class B Certificates pursuant to clauses (iv) and (v) above, the
amounts shall be expressed as a dollar amount per Class A or Class B
Certificate (other than the Residual Certificate) with a $1,000 Denomination,
and as a dollar amount per Residual Certificate with a $100 Denomination.

      Within a reasonable period of time after the end of each calendar year,
the Paying Agent shall, upon request, furnish or cause to be furnished to
each Person who at any time during the calendar year was the Holder of a
Certificate a statement containing the information set forth in
clauses (ii) and (iii)(A) above in the case of a Class A Certificateholder
and the information set forth in clauses (iv) and (v)(A) above in the case of
a Class B Certificateholder aggregated for such calendar year or applicable
portion thereof during which such Person was a Certificateholder. Such
obligation of the Paying Agent shall be deemed to have been satisfied to the
extent that substantially comparable information shall be provided by the
Master Servicer or the Trustee pursuant to any requirements of the Code from
time to time in force.

      Unless the Master Servicer is acting as the Paying Agent, prior to the
close of business on the second Business Day preceding each Distribution
Date, the Master Servicer shall furnish a statement to any Paying Agent (the
information in such statement to be made available to Certificateholders by
the Paying Agent on written request) setting forth the Class A Distribution
Amount with respect to each Class of Class A Certificates and the Class B
Distribution Amount with respect to each Class of Class B Certificates. The
determination by the Master Servicer of such amounts shall, in the absence of
obvious error, be presumptively deemed to be correct for all purposes
hereunder and the Trustee and the Paying Agent shall be protected in relying
upon the same without any independent check or verification.

      In addition to the Distribution Date Statements and the annual
statements required pursuant to this Section 4.04(a), the Paying Agent shall
make available upon request to each Holder and each proposed transferee of a
Class B-4, Class B-5 or Class B-6 Certificate such additional information, if
any, as may be required to permit the proposed transfer to be effected
pursuant to Rule 144A, which information shall be provided on a timely basis
to the Paying Agent by the Master Servicer.

      (b) The Master Servicer's responsibility for disbursing the information
set forth in subsection (a) of this Section 4.04 to each Holder of a
Certificate, the Depositor and other interested parties is limited to the
availability, timeliness and the accuracy of the information provided by each
Servicer. The Master Servicer will make a copy of each Distribution Date
Statement provided pursuant to this Section 4.04 (and, at its option, any
additional files containing the same information in an alternative format)
available each month to Certificateholders and other interested parties, and
other parties to this Agreement via the Master Servicer's internet website,
which in the case of Wells Fargo Bank, is located at "www.ctslink.com."  In
addition, the Paying Agent shall provide copies of the Distribution Date
Statement and the annual statements required pursuant to Section 4.04(a) to
Persons making written requests therefor at its Corporate Trust Office.
Assistance in using the internet website can be obtained by calling the
Master Servicer's customer service desk, which in the case of Wells Fargo
Bank is at (866) 846-4526. Parties that are unable to use the above
distribution method are entitled to have a paper copy mailed to them via
first class mail by calling the customer service desk and indicating such.
The Master Servicer shall have the right to change the way the Distribution
Date Statement is distributed in order to make such distribution more
convenient and/or more accessible and the Master Servicer shall provide
timely and adequate notification to the Certificateholders and the parties to
this Agreement regarding any such changes.

      The Master Servicer shall also be entitled to rely on but shall not be
responsible for the content or accuracy of any information provided by third
parties for purposes of preparing the Distribution Date Statement and may
affix thereto any disclaimer it deems appropriate in its reasonable
discretion (without suggesting liability on the part of any other party
hereto).

      Section 4.05 Grantor Trust Administration. (a) The Master Servicer
shall treat the portions of the Trust Estate consisting of any interests in
the Exchangeable REMIC Certificates beneficially owned in the form of
Exchangeable Certificates and rights with respect thereto as a "grantor
trust" under the Code, and the provisions hereof shall be interpreted
consistently with this treatment. The Master Servicer shall make available
upon request to the Holders of the Exchangeable Certificates, and shall file
or cause to be filed with the Internal Revenue Service together with any
other information or form as may be applicable, their allocable shares of
income and expenses with respect to the property held by the Grantor Trust,
at the time or times and in the manner required by the Code. Under no
circumstances shall the Master Servicer have the power to vary the
investments of the Certificateholders in their related assets of the Grantor
Trust in order to take advantage of variations in this market to improve
their rate of return.

      (b) (i) Each beneficial owner of Exchangeable REMIC Certificates that
elects to hold its interest in the Exchangeable REMIC Certificates in the
form of Exchangeable Certificates pursuant to Sections 5.03 and 5.04 of this
Agreement shall be deemed to have instructed the Master Servicer to deposit
the applicable Exchangeable REMIC Certificates into the Grantor Trust and all
distributions in respect of such Exchangeable REMIC Certificates shall be
deposited into the Exchangeable Certificate Grantor Trust Account. The
Exchangeable Certificate Grantor Trust Account may be deemed a sub-account of
the Certificate Account.

      (ii) On each Distribution Date, the Master Servicer shall deposit all
distributions in respect of the Exchangeable REMIC Certificates deemed
received by it from the Certificate Account pursuant to paragraph (b)(i) of
this Section 4.05 in the Exchangeable Certificate Grantor Trust Account, and
shall immediately distribute such amounts in respect of the Related
Exchangeable Certificates.

      (iii) Any beneficial owner of Exchangeable Certificates that exchanges
such Exchangeable Certificates for the Related Exchangeable REMIC
Certificates shall be deemed to have instructed the Master Servicer to remove
such Exchangeable REMIC Certificates from the Grantor Trust, so that
distributions on such Exchangeable REMIC Certificates are made directly from
the Certificate Account to such beneficial owner.

      (c) The Grantor Trust is a WHFIT that is a WHMT. The Master Servicer
shall report as required under the WHFIT Regulations, provided that the
Master Servicer receives on a timely basis any and all information not
already in its possession reasonably necessary for it to do so. The Master
Servicer is hereby directed to assume that DTC is the only "middleman" (as
such term is defined in the WHFIT Regulations) unless the Depositor provides
the Master Servicer with the identities of other "middlemen" that are
Certificateholders. The Master Servicer shall be entitled to rely on the
first sentence of this subparagraph (c) and shall be entitled to
indemnification in accordance with the terms of this Agreement in the event
that the Internal Revenue Service makes a determination that the first
sentence of this subparagraph (c) is incorrect.

      (d) The Master Servicer shall report required WHFIT information using
the accrual method, except to the extent the WHFIT Regulations specifically
require a different method. The Master Servicer is under no obligation to
determine whether any Certificateholder or other beneficial owner of a
Certificate, to the extent the Master Servicer knows of any other beneficial
owner of a Certificate, uses the cash or accrual method. The Master Servicer
shall make available information as required by the WHFIT Regulations to
Certificateholders annually. In addition, the Master Servicer is not
responsible or liable for providing subsequently amended, revised or updated
information to any Certificateholder, unless requested by the
Certificateholder.

      (e) The Master Servicer shall not be liable for failure to meet the
reporting requirements of the WHFIT Regulations nor for any penalties
thereunder if such failure is due to: (i) the lack of reasonably necessary
information that is not in its possession being provided to the Master
Servicer, (ii) incomplete, inaccurate or untimely information being provided
to the Master Servicer or (iii) the inability of the Master Servicer, after
good faith efforts, to alter its existing information reporting systems to
capture information necessary to fully comply with the WHFIT Regulations for
the 2007 calendar year. Absent receipt of information regarding any sale of
securities, including the price, amount of proceeds and date of sale from the
beneficial owner thereof or the Depositor, the Master Servicer will assume
there is no secondary market trading of WHFIT interests.

      (f) To the extent required by the WHFIT Regulations, the Master
Servicer shall use reasonable efforts to publish on an appropriate website
the CUSIP Numbers for the Certificates that represent ownership of a WHFIT.
The CUSIP Numbers so published will represent the Rule 144A CUSIP Numbers, if
applicable. The Master Servicer shall make reasonable good faith efforts to
keep the website accurate and updated to the extent CUSIP Numbers have been
received. The Master Servicer is not liable for investor reporting delays
that result from the receipt of inaccurate or untimely CUSIP Number
information.

      (g)  The Master Servicer shall be entitled to additional reasonable
compensation for changes in reporting required in respect of the WHFIT
Regulations that arise as a result of  a change in the WHFIT Regulations or a
change in interpretation of the WHFIT Regulations by the Internal Revenue
Service, if such change requires, in the Master Servicer's sole discretion, a
material increase in the Master Servicer's reporting obligations in respect
of the related Grantor Trust.

      Section 4.06 Calculation of Amounts; Binding Effect of Interpretations
and Actions of Master Servicer.

      The Master Servicer will compute the amount of all distributions to be
made on the Certificates and all losses to be allocated to the Certificates.
The Master Servicer will compute all amounts with respect to the Exchangeable
REMIC Certificates and Exchangeable Certificates necessary for preparing the
Distribution Date Statement. In the event that the Master Servicer concludes
that any ambiguity or uncertainty exists in any provisions of this Agreement
relating to distributions to be made on the Certificates, the allocation of
losses to the Certificates or otherwise, the interpretation of such
provisions and any actions taken by the Master Servicer in good faith to
implement such interpretation shall be binding upon Certificateholders.

      Section 4.07 Reserved.

      Section 4.08 Distributions on Exchangeable Certificates.  On each
Distribution Date, the Master Servicer shall withdraw from the Exchangeable
Certificate Grantor Trust Account the amount distributable for each Class of
Exchangeable Certificates and shall make the appropriate distributions to the
Certificateholders of each such Class. All distributions that are made with
respect to a particular Class of Exchangeable Certificates shall be made pro
rata among all Outstanding Certificates of such Class in proportion to their
respective Percentage Interests, with no preference or priority of any kind.

                                    ARTICLE V

                                THE CERTIFICATES

      Section 5.01 The Certificates.

      (a) The Class A and Class B Certificates shall be issued only in
minimum Denominations of a Single Certificate and, except for the Residual
Certificate, integral multiples of $1 in excess thereof and shall be
substantially in the respective forms set forth as Exhibits A-1, A-2, A-3,
A-PO, A-R, B-1, B-2, B-3, B-4, B-5, B-6 and C (reverse side of Certificates)
hereto. On original issue the Certificates shall be executed and delivered by
the Paying Agent to or upon the order of the Depositor upon receipt by the
Trustee or the Custodian of the documents specified in Section 2.01(a). The
aggregate principal portion evidenced by the Class A and Class B Certificates
shall be the sum of the amounts specifically set forth in the respective
Certificates. The Certificates shall be executed by manual or facsimile
signature on behalf of the Paying Agent by any Responsible Officer thereof.
Certificates bearing the manual or facsimile signatures of individuals who
were at any time the proper officers of the Paying Agent shall bind the
Paying Agent notwithstanding that such individuals or any of them have ceased
to hold such offices prior to the countersigning of such Certificates and
delivery of such Certificates or did not hold such offices at the date of
such Certificates. No Certificate shall be entitled to any benefit under this
Agreement, or be valid for any purpose, unless manually countersigned by a
Responsible Officer of the Authenticating Agent, or unless there appears on
such Certificate a certificate of authentication executed by the
Authenticating Agent by manual signature, and such countersignature or
certificate upon a Certificate shall be conclusive evidence, and the only
evidence, that such Certificate has been duly authenticated and delivered
hereunder. All Certificates shall be dated the date of their authentication.

      Until such time as Definitive Certificates are issued pursuant to
Section 5.09, each Book-Entry Certificate shall bear the following legend:

      "Unless this certificate is presented by an authorized representative
of [the Clearing Agency] to the Depositor or its agent for registration of
transfer, exchange or payment, and any certificate issued is registered in
the name of [the Clearing Agency] or such other name as requested by an
authorized representative of [the Clearing Agency] and any payment is made to
[the Clearing Agency], any transfer, pledge or other use hereof for value or
otherwise by or to any person is wrongful since the registered owner hereof,
[the Clearing Agency], has an interest herein."

      (b) Upon original issuance, the Book-Entry Certificates shall be issued
in the form of one or more typewritten certificates, to be delivered to DTC,
the initial Clearing Agency, by, or on behalf of, the Depositor or to, and
deposited with the Certificate Custodian, on behalf of DTC, if directed to do
so pursuant to instructions from DTC. Such Certificates shall initially be
registered in the Certificate Register in the name of the nominee of the
initial Clearing Agency, and no Beneficial Owner will receive a definitive
certificate representing such Beneficial Owner's interest in the Book-Entry
Certificates, except as provided in Section 5.09. Unless and until
definitive, fully registered certificates ("Definitive Certificates") have
been issued to Beneficial Owners pursuant to Section 5.09:

      (i) the provisions of this Section 5.01(b) shall be in full force and
   effect;

      (ii) the Depositor, the Master Servicer, the Certificate Registrar, the
   Paying Agent and the Trustee may deal with the Clearing Agency for all
   purposes (including the making of distributions on the Book-Entry
   Certificates and the taking of actions by the Holders of Book-Entry
   Certificates) as the authorized representative of the Beneficial Owners;

      (iii) to the extent that the provisions of this Section 5.01(b)
   conflict with any other provisions of this Agreement, the provisions of
   this Section 5.01(b) shall control;

      (iv) the rights of Beneficial Owners shall be exercised only through
   the Clearing Agency and shall be limited to those established by law, the
   rules, regulations and procedures of the Clearing Agency and agreements
   between such Beneficial Owners and the Clearing Agency and/or the Clearing
   Agency Participants, and all references in this Agreement to actions by
   Certificateholders shall, with respect to the Book-Entry Certificates,
   refer to actions taken by the Clearing Agency upon instructions from the
   Clearing Agency Participants, and all references in this Agreement to
   distributions, notices, reports and statements to Certificateholders
   shall, with respect to the Book-Entry Certificates, refer to
   distributions, notices, reports and statements to the Clearing Agency or
   its nominee, as registered holder of the Book-Entry Certificates, as the
   case may be, for distribution to Beneficial Owners in accordance with the
   procedures of the Clearing Agency; and

      (v) the initial Clearing Agency will make book-entry transfers among
   the Clearing Agency Participants and receive and transmit distributions of
   principal and interest on the Certificates to the Clearing Agency
   Participants, for distribution by such Clearing Agency Participants to the
   Beneficial Owners or their nominees.

      For purposes of any provision of this Agreement requiring or permitting
actions with the consent of, or at the direction of, Holders of Book-Entry
Certificates evidencing specified Voting Interests, such direction or consent
shall be given by Beneficial Owners having the requisite Voting Interests,
acting through the Clearing Agency.

      Unless and until Definitive Certificates have been issued to Beneficial
Owners pursuant to Section 5.09, copies of the Distribution Date Statements
shall be available to Beneficial Owners upon written request to the Paying
Agent at its Corporate Trust Office.

      Section 5.02 Registration of Certificates.

      (a) The Certificate Registrar shall cause to be kept at one of the
offices or agencies to be maintained in accordance with the provisions of
Section 5.08 a Certificate Register in which, subject to such reasonable
regulations as it may prescribe, the Certificate Registrar shall provide for
the registration of Certificates and of transfers and exchanges of
Certificates as herein provided. The Master Servicer shall act as, or shall
appoint, a Certificate Registrar for the purpose of registering Certificates
and transfers and exchanges of Certificates as herein provided.

      Upon surrender for registration of transfer of any Certificate at any
office or agency maintained for such purpose pursuant to Section 5.08 (and
subject to the provisions of this Section 5.02) the Paying Agent shall
execute, and shall date, countersign (or cause the Authenticating Agent to
countersign) and deliver, in the name of the designated transferee or
transferees, one or more new Certificates of a like aggregate principal
portion or Percentage Interest and of the same Class.

      At the option of the Certificateholders, Certificates may be exchanged
for other Certificates of authorized Denominations of a like aggregate
principal portion or Percentage Interest and of the same Class upon surrender
of the Certificates to be exchanged at any such office or agency. Whenever
any Certificates are so surrendered for exchange, the Paying Agent shall
execute, and shall date, countersign (or cause the Authenticating Agent to
countersign) and deliver, the Certificates which the Certificateholder making
the exchange is entitled to receive. Every Certificate presented or
surrendered for transfer or exchange shall (if so required by the Certificate
Registrar or the Paying Agent) be duly endorsed by, or be accompanied by a
written instrument of transfer in form satisfactory to the Certificate
Registrar, duly executed by the Holder thereof or his attorney duly
authorized in writing.

      No service charge shall be made for any transfer or exchange of
Certificates, but the Certificate Registrar may require payment of a sum
sufficient to cover any tax or governmental charge that may be imposed in
connection with any transfer or exchange of Certificates.

      All Certificates surrendered for transfer and exchange shall be
canceled by the Certificate Registrar, the Paying Agent or the Authenticating
Agent in accordance with their standard procedures.

      (b) No transfer of a Class B-4, Class B-5 or Class B-6 Certificate
shall be made unless the registration requirements of the 1933 Act and any
applicable State securities laws are complied with, or such transfer is
exempt from the registration requirements under said Act and laws. In the
event that a transfer is to be made in reliance upon an exemption from said
Act or laws, the Master Servicer shall require the transferee (other than an
affiliate of the Depositor on the Closing Date) to execute an investment
letter in the form of Exhibit J hereto certifying to the Depositor and the
Master Servicer the facts surrounding such transfer, which investment letter
shall not be an expense of the Depositor or the Master Servicer. The Holder
of a Class B-4, Class B-5 or Class B-6 Certificate desiring to effect such
transfer shall, and does hereby agree to, indemnify the Trustee, the
Depositor, the Master Servicer and any Paying Agent against any liability
that may result if the transfer is not so exempt or is not made in accordance
with such federal and state laws. Neither the Depositor nor the Master
Servicer is under an obligation to register the Class B-4, Class B-5 or Class
B-6 Certificates under said Act or any other securities law. For the purposes
of this Section 5.02(b) the representations required in any investment letter
(in substantially the form attached hereto as Exhibit J for any transfer of a
Class B-4, Class B-5 or Class B-6 Certificate) shall be deemed to have been
made in connection with the transfer of any Class B-4, Class B-5 or Class B-6
Certificate that is a Book-Entry Certificate.

      (c) No transfer of a Class B-4, Class B-5 or Class B-6 Certificate
shall be made (other than to an affiliate of the Depositor on the Closing
Date) unless the Master Servicer and the Depositor shall have received (i) a
representation letter from the transferee in the form of Exhibit J hereto, to
the effect that either (a) such transferee is not an employee benefit plan or
other retirement arrangement subject to Title I of ERISA or Code Section
4975, or a governmental plan, as defined in Section 3(32) of ERISA, subject
to any federal, state or local law ("Similar Law") which is to a material
extent similar to the foregoing provisions of ERISA or the Code
(collectively, a "Plan") and is not a person acting on behalf of or using the
assets of any such Plan, which representation letter shall not be an expense
of the Depositor or the Master Servicer or (b) if such transferee is an
insurance company, (A) the source of funds used to purchase the Class B-4,
Class B-5 or Class B-6 Certificate is an "insurance company general account"
(as such term is defined in Section V(e) of Prohibited Transaction Class
Exemption 95-60 ("PTE 95-60"), 60 Fed. Reg. 35925 (July 12, 1995)), (B) there
is no Plan with respect to which the amount of such general account's
reserves and liabilities for the contract(s) held by or on behalf of such
Plan and all other Plans maintained by the same employer (or affiliate
thereof as defined in Section V(a)(1) of PTE 95-60) or by the same employee
organization exceeds 10% of the total of all reserves and liabilities of such
general account (as such amounts are determined under Section I(a) of PTE
95-60) at the date of acquisition and (C) the purchase and holding of such
Class B-4, Class B-5 or Class B-6 Certificate is covered by Sections I and
III of PTE 95-60 or (ii) in the case of any such Class B-4, Class B-5 or
Class B-6 Certificate presented for registration in the name of a Plan, or a
trustee of any such Plan, (A) an Opinion of Counsel satisfactory to the
Master Servicer and the Depositor to the effect that the purchase or holding
of such Class B-4, Class B-5 or Class B-6 Certificate will not constitute or
result in a non-exempt prohibited transaction within the meaning of ERISA,
Section 4975 of the Code or Similar Law and will not subject the Depositor or
the Master Servicer to any obligation in addition to those undertaken in this
Agreement, which Opinion of Counsel shall not be an expense of the Depositor
or the Master Servicer and (B) such other opinions of counsel, Officer's
Certificates and agreements as the Depositor or the Master Servicer may
require in connection with such transfer, which opinions of counsel,
Officer's Certificates and agreements shall not be an expense of the
Depositor or the Master Servicer. The applicable representation set forth in
clause (i) shall be deemed to have been made to the Depositor and Master
Servicer by the acceptance by a transferee of the beneficial interest in any
Class B-4, Class B-5 and Class B-6 Certificates, unless the Depositor and
Master Servicer shall have received from the transferee either an alternative
representation acceptable in form and substance to the Depositor and Master
Servicer or the Opinion of Counsel and other documentation set forth in
clause (ii). The Class B-4, Class B-5 and Class B-6 Certificates shall bear a
legend referring to the foregoing restrictions contained in this paragraph.

      (d) No legal or beneficial interest in all or any portion of the
Residual Certificate may be transferred directly or indirectly to a
"disqualified organization" within the meaning of Code Section 860E(e)(5) or
an agent of a disqualified organization (including a broker, nominee, or
middleman), to a Plan or a Person acting on behalf of or investing the assets
of a Plan (such Plan or Person, an "ERISA Prohibited Holder") or to an
individual, corporation, partnership or other person unless such transferee
(i) is not a Non-U.S. Person or (ii) is a Non-U.S. Person that holds the
Residual Certificate in connection with the conduct of a trade or business
within the United States and has furnished the transferor and the Master
Servicer with an effective Internal Revenue Service Form W-8ECI or (iii) is a
Non-U.S. Person that has delivered to both the transferor and the Master
Servicer an opinion of a nationally recognized tax counsel to the effect that
the transfer of the Residual Certificate to it is in accordance with the
requirements of the Code and the regulations promulgated thereunder and that
such transfer of the Residual Certificate will not be disregarded for federal
income tax purposes (any such person who is not covered by clauses (i), (ii)
or (iii) above being referred to herein as a "Non-permitted Foreign Holder"),
and any such purported transfer shall be void and have no effect. The Paying
Agent shall not execute, and shall not countersign (or cause the
Authenticating Agent to countersign) and deliver, a new Residual Certificate
in connection with any such transfer to a disqualified organization or agent
thereof (including a broker, nominee or middleman), an ERISA Prohibited
Holder or a Non-permitted Foreign Holder, and neither the Certificate
Registrar nor the Paying Agent shall accept a surrender for transfer or
registration of transfer, or register the transfer of, the Residual
Certificate, unless the transferor shall have provided to the Master Servicer
an affidavit, substantially in the form attached as Exhibit H hereto, signed
by the transferee, to the effect that the transferee is not such a
disqualified organization, an agent (including a broker, nominee, or
middleman) for any entity as to which the transferee has not received a
substantially similar affidavit, an ERISA Prohibited Holder or a
Non-permitted Foreign Holder, which affidavit shall contain the consent of
the transferee to any such amendments of this Agreement as may be required to
further effectuate the foregoing restrictions on transfer of the Residual
Certificate to disqualified organizations, ERISA Prohibited Holders or
Non-permitted Foreign Holders. Such affidavit shall also contain the
statement of the transferee that (i) the transferee has historically paid its
debts as they have come due and intends to do so in the future, (ii) the
transferee understands that it may incur liabilities in excess of cash flows
generated by the residual interest, (iii) the transferee intends to pay taxes
associated with holding the residual interest as they become due (iv) the
transferee will not cause income from the Residual Certificate to be
attributable to a foreign permanent establishment or fixed base, within the
meaning of an applicable income tax treaty, of such transferee or any other
Person, and (v) the transferee will not transfer the Residual Certificate to
any Person who does not provide an affidavit substantially in the form
attached as Exhibit H hereto.

      The affidavit described in the preceding paragraph, if not executed in
connection with the initial issuance of the Residual Certificate, shall be
accompanied by a written statement in the form attached as Exhibit I hereto,
signed by the transferor, to the effect that as of the time of the transfer,
the transferor has no actual knowledge that the transferee is a disqualified
organization, ERISA Prohibited Holder or Non-permitted Foreign Holder, and
has no knowledge or reason to know that the statements made by the transferee
with respect to clauses (i) and (iii) of the last sentence of the preceding
paragraph are not true. The Residual Certificate shall bear a legend
referring to the foregoing restrictions contained in this paragraph and the
preceding paragraph.

      Upon actual knowledge of a Master Servicing Officer or a Responsible
Officer of the Paying Agent that any legal or beneficial interest in any
portion of the Residual Certificate has been transferred, directly or
indirectly, to a disqualified organization or agent thereof (including a
broker, nominee, or middleman) in contravention of the foregoing
restrictions, (i) such transferee shall be deemed to hold the Residual
Certificate in constructive trust for the last transferor who was not a
disqualified organization or agent thereof, and such transferor shall be
restored as the owner of such Residual Certificate as completely as if such
transfer had never occurred, provided that the Master Servicer may, but is
not required to, recover any distributions made to such transferee with
respect to the Residual Certificate, and (ii) the Master Servicer agrees to
furnish to the Internal Revenue Service and to any transferor of the Residual
Certificate or such agent (within 60 days of the request therefor by the
transferor or agent) such information necessary to the application of Code
Section 860E(e) as may be required by the Code, including but not limited to
the present value of the total anticipated excess inclusions with respect to
the Residual Certificate (or portion thereof) for periods after such
transfer. At the election of the Master Servicer, the cost to the Master
Servicer of computing and furnishing such information may be charged to the
transferor or such agent referred to above; however, the Master Servicer
shall in no event be excused from furnishing such information.

      Section 5.03 Transfer of Exchangeable REMIC Certificates and
Exchangeable Certificates.  (a)  Upon the presentation and surrender by any
Certificateholder of its Exchangeable REMIC Certificates or Exchangeable
Certificates in the appropriate combination as set forth in Exhibit W hereto,
such Certificateholder shall hereunder transfer, assign, set over and
otherwise convey to the Master Servicer, all of such Certificateholder's
right, title and interest in and to such Exchangeable REMIC Certificates or
Exchangeable Certificates, including all payments of interest thereon
received after the date of such presentation and surrender and until such
Certificateholder informs the Master Servicer that it wishes to again hold
its interest in the form of Exchangeable REMIC Certificates or Exchangeable
Certificates, as applicable.

      (b) The Master Servicer acknowledges any transfer and assignment of
Exchangeable REMIC Certificates or Exchangeable Certificates pursuant to the
foregoing paragraph, and hereby declares that it will hold the same in trust
for the Certificateholders on the terms in this Agreement, and shall treat
such Exchangeable REMIC Certificates and Exchangeable Certificates in
accordance with Section 4.08 of this Agreement.

      Section 5.04 Exchanges of Exchangeable REMIC Certificates and
Exchangeable Certificates.  (a)  Exchangeable REMIC Certificates shall be
exchangeable on the books of DTC for Exchangeable Certificates, and
Exchangeable Certificates shall be exchangeable on the books of DTC for
Exchangeable REMIC Certificates, after the Closing Date, by notice to the
Master Servicer substantially in the form of Exhibit X hereto or, under the
terms and conditions hereinafter set forth and otherwise in accordance with
the procedures specified in this Agreement.

      (b) In the case of each Combination Group, Certificates of the Class or
Classes of Exchangeable REMIC Certificates in such Combination Group shall be
exchangeable for Certificates of the Class or Classes of Exchangeable
Certificates in such Combination Group in respective Denominations,
determined based on the proportion that the Maximum Initial Principal
Balances of the Class or Classes of Exchangeable REMIC Certificates bear to
the Maximum Initial Principal Balances of the Class or Classes of Related
Exchangeable Certificates, as set forth in Exhibit W hereto. Except as
provided in Section 4.08 of this Agreement, upon any such exchange, the
portions of the Exchangeable REMIC Certificates designated for exchange shall
be deemed cancelled and replaced by the Exchangeable Certificates issued in
exchange therefor. Correspondingly, Certificates of the Class or Classes of
Exchangeable Certificates in a Combination Group may be further designated
for exchange for Certificates of the Class or Classes of Exchangeable REMIC
Certificates in such Combination Group in respective Denominations,
determined based on the proportion that the Maximum Initial Principal
Balances of the Class or Classes of Exchangeable Certificates bear to the
Maximum Initial Principal Balances of the Class or Classes of Related
Exchangeable REMIC Certificates, as set forth in Exhibit W hereto. There
shall be no limitation on the number of exchanges authorized pursuant to this
Section 5.04, and, except as provided below, no fee or other charge shall be
payable to the Master Servicer or DTC in connection therewith.

      (c) In order to effect an exchange of Exchangeable REMIC Certificates
or Exchangeable Certificates, the Certificateholder shall notify the Master
Servicer by e-mail at ctsspgexchanges@wellsfargo.com no later than two
Business Days before the proposed exchange date. The exchange date can be any
Business Day from the 25th day of the month through the second to the last
Business Day of the month, subject to the Master Servicer's approval. In
addition, the Certificateholder must provide notice on the
Certificateholder's letterhead, which notice must carry a medallion stamp
guarantee and set forth the following information: the CUSIP number of each
Exchangeable REMIC Certificate or Exchangeable Certificate to be exchanged
and Exchangeable REMIC Certificate or Exchangeable Certificate to be
received; the outstanding principal balance and the portion of the Maximum
Initial Principal Balance of the Exchangeable REMIC Certificates or
Exchangeable Certificates to be exchanged; the Certificateholder's DTC
participant number; and the proposed exchange date. After receiving the
notice, the Master Servicer shall e-mail the Certificateholder with wire
payment instructions relating to the exchange fee. The Certificateholder will
utilize the "deposit and withdrawal system" at DTC to exchange the
Certificates. If there is an error, the exchange will not occur until such
error is corrected. A notice becomes irrevocable on the second Business Day
before the proposed exchange date.

      Notwithstanding any other provision herein set forth, an exchange fee
of $5,000 shall be payable to the Master Servicer in connection with each
exchange.

      The Master Servicer shall make the first distribution on an
Exchangeable REMIC Certificate or Exchangeable Certificate received in an
exchange transaction on the Distribution Date in the month following the
month of the exchange to the Certificateholder of record as of the applicable
Record Date for such Certificate.

      Section 5.05 Mutilated, Destroyed, Lost or Stolen Certificates.

      If (i) any mutilated Certificate is surrendered to the Paying Agent,
the Certificate Registrar or the Authenticating Agent, or the Paying Agent,
the Certificate Registrar or the Authenticating Agent receives evidence to
its satisfaction of the destruction, loss or theft of any Certificate, and
(ii) there is delivered to the Paying Agent, the Certificate Registrar or the
Authenticating Agent such security or indemnity as may be required by them to
hold each of them harmless, then, in the absence of notice to the Paying
Agent, the Certificate Registrar or the Authenticating Agent that such
Certificate has been acquired by a bona fide purchaser, the Paying Agent
shall execute and countersign (or cause the Authenticating Agent to
countersign) and deliver, in exchange for or in lieu of any such mutilated,
destroyed, lost or stolen Certificate, a new Certificate of like tenor and
principal portion or Percentage Interest and of the same Class. Upon the
issuance of any new Certificate under this Section, the Paying Agent or the
Certificate Registrar may require the payment of a sum sufficient to cover
any tax or other governmental charge that may be imposed in relation thereto
and any other expense (including the fees and expenses of the Paying Agent or
the Authenticating Agent) in connection therewith. Any duplicate Certificate
issued pursuant to this Section shall constitute complete and indefeasible
evidence of ownership in the Trust Estate, as if originally issued, whether
or not the lost, stolen, or destroyed Certificate shall be found at any time.

      Section 5.06 Persons Deemed Owners.

      Prior to the due presentation of a Certificate for registration of
transfer, the Depositor, the Master Servicer, the Trustee, the Paying Agent,
the Certificate Registrar and any agent of the Depositor, the Master
Servicer, the Trustee, the Paying Agent or the Certificate Registrar may
treat the Person in whose name any Certificate is registered as the owner of
such Certificate for the purpose of receiving distributions pursuant to
Section 4.01, and for all other purposes whatsoever, and neither the
Depositor, the Master Servicer, the Trustee, the Certificate Registrar, the
Paying Agent nor any agent of the Depositor, the Master Servicer, the
Trustee, the Certificate Registrar or the Paying Agent shall be affected by
notice to the contrary.

      Section 5.07 Access to List of Certificateholders' Names and Addresses.

      (a) If the Paying Agent is not acting as Certificate Registrar, the
Certificate Registrar shall furnish or cause to be furnished to the Paying
Agent, within 15 days after receipt by the Certificate Registrar of a request
by the Paying Agent in writing, a list, in such form as the Paying Agent may
reasonably require, of the names and addresses of the Certificateholders of
each Class as of the most recent Record Date.

      (b) If five or more Certificateholders (hereinafter referred to as
"applicants") apply in writing to the Certificate Registrar, and such
application states that the applicants desire to communicate with other
Certificateholders with respect to their rights under this Agreement or under
the Certificates and is accompanied by a copy of the communication which such
applicants propose to transmit, then the Certificate Registrar shall, within
five Business Days following the receipt of such application, afford such
applicants access during normal business hours to the most recent list of
Certificateholders held by the Certificate Registrar.

      (c) Every Certificateholder, by receiving and holding a Certificate,
agrees with the Depositor, the Master Servicer, the Certificate Registrar,
the Paying Agent and the Trustee that neither the Depositor, the Master
Servicer, the Certificate Registrar, the Paying Agent nor the Trustee shall
be held accountable by reason of the disclosure of any such information as to
the names, addresses and Percentage Interests of the Certificateholders
hereunder, regardless of the source from which such information was delivered.

      Section 5.08 Maintenance of Office or Agency.

      The Certificate Registrar will maintain, at its expense, an office or
agency where Certificates may be surrendered for registration of transfer or
exchange and where notices and demands to or upon the Certificate Registrar
in respect of the Certificates and this Agreement may be served. The
Certificate Registrar initially designates the Corporate Trust Office of the
Certificate Registrar, if any, as its offices and agencies for said purposes.

      Section 5.09 Definitive Certificates.

      If (A) the Clearing Agency advises the Paying Agent in writing that the
Clearing Agency is no longer willing or able properly to discharge its
responsibilities as depository with respect to the Book-Entry Certificates,
and (B) the Depositor is unable to locate a qualified successor, the Paying
Agent shall notify the Beneficial Owners, through the Clearing Agency, of the
occurrence of any such event and of the availability of Definitive
Certificates to Beneficial Owners requesting the same. Upon surrender to the
Paying Agent by the Clearing Agency of the Certificates held of record by its
nominee, accompanied by reregistration instructions and directions to execute
and authenticate new Certificates from the Depositor, the Paying Agent shall
execute and cause the Authenticating Agent to countersign Definitive
Certificates for delivery at its Corporate Trust Office. The Depositor shall
arrange for, and will bear all costs of, the printing and issuance of such
Definitive Certificates. Except with the consent of the Depositor, the Paying
Agent shall not execute or cause the Authenticating Agent to countersign
Definitive Certificates in exchange for Book-Entry Certificates except as set
forth above. Neither the Depositor, the Master Servicer nor the Paying Agent
shall be liable for any delay in delivery of such instructions by the
Clearing Agency and may conclusively rely on, and shall be protected in
relying on, such instructions.

      Section 5.10 Notices to Clearing Agency.

      Whenever notice or other communication to the Holders of Book-Entry
Certificates is required under this Agreement, unless and until Definitive
Certificates shall have been issued to Beneficial Owners pursuant to Section
5.09, the Paying Agent shall give all such notices and communications
specified herein to be given to Holders of Book-Entry Certificates to the
Clearing Agency.

                                   ARTICLE VI

                      THE DEPOSITOR AND THE MASTER SERVICER

      Section 6.01 Liability of the Depositor and the Master Servicer.

      The Depositor and the Master Servicer shall each be liable in
accordance herewith only to the extent of the obligations specifically
imposed by this Agreement and undertaken hereunder by the Depositor and the
Master Servicer.

      Section 6.02 Merger or Consolidation of the Depositor or the Master
Servicer.

      Subject to the following paragraph (a) the Depositor will keep in full
effect its existence, rights and franchises as a corporation under the laws
of the jurisdiction of its incorporation, and will obtain and preserve its
qualification to do business as a foreign corporation in each jurisdiction in
which such qualification is or shall be necessary to protect the validity and
enforceability of this Agreement, the Certificates or any of the Mortgage
Loans and to perform its respective duties under this Agreement and (b) the
Master Servicer will keep in full effect its power and authority as a
national banking association under the laws of the jurisdiction of its
organization, and will obtain and preserve its qualification to do business
in each jurisdiction in which such qualification is or shall be necessary to
protect the validity and enforceability of this Agreement, the Certificates
or any of the Mortgage Loans and to perform its respective duties under this
Agreement.

      The Depositor or the Master Servicer may be merged or consolidated with
or into any Person, or transfer all or substantially all of its assets to any
Person, in which case any Person resulting from any merger or consolidation
to which the Depositor or Master Servicer shall be a party, or any Person
succeeding to the business of the Depositor or Master Servicer, shall be the
successor of the Depositor or Master Servicer hereunder, without the
execution or filing of any paper or any further act on the part of any of the
parties hereto, anything herein to the contrary notwithstanding; provided,
however, that, (a) in the case of the Master Servicer, any such successor or
resulting Person shall have a net worth of not less than $15,000,000 and be
qualified to service mortgage loans for Fannie Mae or Freddie Mac and (b) the
Master Servicer and such successor or surviving Person shall notify the
Depositor and the Trustee of any such merger, conversion or consolidation at
least two Business Days prior to the effective date thereof (unless giving
such prior notice would be prohibited by applicable law or by a
confidentiality agreement, in which case notice shall be given by 12 noon
Eastern time one Business Day after such merger or consolidation).

      Section 6.03 Limitation on Liability of the Depositor, the Master
Servicer and Others.

      Neither the Depositor nor the Master Servicer nor any subcontractor nor
any of the directors, officers, employees or agents of any of them shall be
under any liability to the Trust Estate or the Certificateholders and all
such Persons shall be held harmless for any action taken or for refraining
from the taking of any action in good faith pursuant to this Agreement, or
for errors in judgment; provided, however, that this provision shall not
protect any such Person against any breach of warranties or representations
made herein or against any liability which would otherwise be imposed by
reason of willful misfeasance, bad faith or gross negligence in the
performance of duties or by reason of reckless disregard of obligations and
duties hereunder. The Depositor, the Master Servicer, any subcontractor, and
any director, officer, employee or agent of any of them shall be entitled to
indemnification by the Trust Estate and will be held harmless against any
loss, liability or expense incurred in connection with the performance of
their duties and obligations, the exercise of their rights or any legal
action (including but not limited to, costs and expenses of litigation, and
of investigation, attorney's fees, damages, judgments and amounts paid in
settlement) under this Agreement (in the case of the Depositor, including but
not limited to, any loss, liability, or expense incurred in connection with
the Depositor's indemnification of the Custodian pursuant to the Custodial
Agreement), the Certificates or the Mortgage Loans (except for amounts due by
the Depositor in connection with the breach of a representation or warranty
covering the Mortgage Loans), including, in the case of the Master Servicer,
any indemnity amounts paid by the Master Servicer to a Servicer pursuant to
the applicable Servicing Agreement, other than any loss, liability or expense
(including without limitation, expenses payable by the Master Servicer under
Section 8.06) incurred by reason of willful misfeasance, bad faith or gross
negligence in the performance of his or its duties hereunder or by reason of
reckless disregard of his or its obligations and duties hereunder. The
Depositor, the Master Servicer and any of the directors, officers, employees
or agents of either may rely in good faith on any document of any kind which,
prima facie, is properly executed and submitted by any Person respecting any
matters arising hereunder. Neither the Depositor nor the Master Servicer
shall be under any obligation to appear in, prosecute or defend any legal
action unless such action is related to its respective duties under this
Agreement and, in its opinion, does not involve it in any expense or
liability; provided, however, that the Depositor or the Master Servicer may
in its discretion undertake any such action which it may deem necessary or
desirable with respect to this Agreement and the rights and duties of the
parties hereto and the interests of the Certificateholders hereunder if the
Certificateholders offer to the Depositor or the Master Servicer, as the case
may be, reasonable security or indemnity against the costs, expenses and
liabilities which may be incurred therein or thereby. In such event, the
legal expenses and costs of such action and any liability resulting therefrom
shall be expenses, costs and liabilities of the Trust Estate, and the
Depositor or the Master Servicer shall be entitled to be reimbursed therefor
out of the Certificate Account, and such amounts shall, on the following
Distribution Date or Distribution Dates, be allocated in reduction of
distributions on the Class A Certificates and Class B Certificates in the
same manner as Realized Losses are allocated pursuant to Section 4.02(a).

      Section 6.04 Resignation of the Master Servicer.

      The Master Servicer shall not resign from the obligations and duties
hereby imposed on it except (a) upon appointment of a successor master
servicer and receipt by the Trustee of a letter from each Rating Agency that
such a resignation and appointment will not result in a downgrading of the
rating of any of the Certificates, (b) upon determination that its duties
hereunder are no longer permissible under applicable law, or (c) pursuant to
Section 6.06. Any such determination under clause (b) permitting the
resignation of the Master Servicer shall be evidenced by an Opinion of
Counsel to such effect delivered to the Trustee. No such resignation shall
become effective until the Trustee or a successor master servicer shall have
assumed the Master Servicer's responsibilities, duties, liabilities and
obligations hereunder.

      Section 6.05 Compensation to the Master Servicer.

      The Master Servicer shall be entitled to receive a monthly fee equal to
the Master Servicing Fee, as compensation for services rendered by the Master
Servicer under this Agreement. The Master Servicer also will be entitled to
any late reporting fees paid by a Servicer pursuant to its Servicing
Agreement, any investment income on funds on deposit in the Certificate
Account invested in accordance with Section 3.01(c), any investment income on
funds on deposit in the Payment Account invested in accordance with Section
4.03(a) and any Liquidation Profits to which a Servicer is not entitled under
its Servicing Agreement.

      Section 6.06 Assignment or Delegation of Duties by Master Servicer.

      (a) The Master Servicer shall not assign or transfer any of its rights,
benefits or privileges under this Agreement to any other Person, or delegate
to or subcontract with, or authorize or appoint any other Person to perform
any of the duties, covenants or obligations to be performed by the Master
Servicer without the prior written consent of the Trustee, and any agreement,
instrument or act purporting to effect any such assignment, transfer,
delegation or appointment shall be void. Notwithstanding the foregoing,
subject to Section 6.06(b), the Master Servicer shall have the right without
the prior written consent of the Trustee (i) to assign its rights and
delegate its duties and obligations hereunder; provided, however, that (a)
the purchaser or transferee accepting such assignment or delegation is
qualified to service mortgage loans for Fannie Mae or Freddie Mac, and
executes and delivers to the Trustee an agreement, in form and substance
reasonably satisfactory to the Trustee, which contains an assumption by such
purchaser or transferee of the due and punctual performance and observance of
each covenant and condition to be performed or observed by the Master
Servicer hereunder from and after the date of such agreement; and (b) each
applicable Rating Agency's rating of any Certificates in effect immediately
prior to such assignment, sale or transfer is not reasonably likely to be
qualified, downgraded or withdrawn as a result of such assignment, sale or
transfer and the Certificates are not reasonably likely to be placed on
credit review status by any such Rating Agency; and (ii) to delegate to,
subcontract with, authorize, or appoint an affiliate of the Master Servicer
to perform and carry out any duties, covenants or obligations to be performed
and carried out by the Master Servicer under this Agreement and hereby agrees
so to delegate, subcontract, authorize or appoint to an affiliate of the
Master Servicer any duties, covenants or obligations to be performed and
carried out by the Master Servicer to the extent that such duties, covenants
or obligations are to be performed in any state or states in which the Master
Servicer is not authorized to do business as a foreign corporation but in
which the affiliate is so authorized. In no case, however, shall any
permitted assignment and delegation relieve the Master Servicer of any
liability to the Trustee or the Depositor under this Agreement, incurred by
it prior to the time that the conditions contained in clause (i) above are
met.

      (b) Notwithstanding anything contained herein to the contrary, to the
extent the Master Servicer engages any affiliate or third party vendor, in
connection with the performance of any of its duties under this Agreement,
the Master Servicer shall immediately notify the Depositor in writing of such
engagement (to the extent it has not already notified the Depositor pursuant
to clause (a) above); provided however, that prior to engaging any affiliate
or third party vendor in connection with the performance of any of its duties
under this Agreement, the Master Servicer shall determine (i) if such
affiliate or third party vendor would be a Servicing Function Participant and
(ii) if such affiliate or third party vendor would be a "servicer" within the
meaning of Item 1101 of Regulation AB (an "Additional Master Servicer") and
meets the criteria in Item 1108(a)(2)(i), (ii) or (iii) of Regulation AB. If
the Master Servicer has determined that such affiliate or third party vendor
is a Servicing Function Participant, the Master Servicer shall cause such
Servicing Function Participant to prepare and deliver to the Master Servicer
a separate assessment and attestation report, as contemplated by Section 3.11
of this Agreement. In addition, if the Master Servicer has determined that
any such affiliate or third party vendor would be an Additional Master
Servicer and meets the criteria in Item 1108(a)(2)(i), (ii) or (iii) of
Regulation AB, the Master Servicer shall cause such Additional Master
Servicer to prepare and deliver to the Master Servicer a separate compliance
statement as contemplated by Section 3.05 of this Agreement. In addition, if
the Master Servicer determines any such affiliate or third party vendor would
be a "servicer" within the meaning of Item 1101 of Regulation AB, the Master
Servicer shall not engage such affiliate or third party vendor unless it
provides the Master Servicer and the Depositor the information required by
Section 1108(b) and 1108(c) of Regulation AB prior to such engagement.

      (c) In the event of any assignment of rights or delegation of duties of
the Master Servicer, the Master Servicer shall report such event on Form 8-K
within four Business Days after the effective date thereof.

      Section 6.07 Indemnification of Trustee and Depositor by Master
Servicer.

      The Master Servicer shall indemnify and hold harmless the Trustee and
the Depositor and any director, officer or agent thereof against any loss,
liability or expense, including reasonable attorney's fees, arising out of,
in connection with or incurred by reason of (a) willful misfeasance, bad
faith or negligence in the performance of duties of the Master Servicer under
this Agreement or by reason of reckless disregard of its obligations and
duties under this Agreement, including, but not limited to the Master
Servicer's obligation to deliver any information, report, certification,
accountants' letter or other material required to comply with Regulation AB
or (b) any material breach by the Master Servicer of any of the
representations and warranties contained in Section 2.03(a). Any payment
pursuant to this Section made by the Master Servicer to the Trustee or the
Depositor shall be from such entity's own funds, without reimbursement
therefor. The provisions of this Section 6.07 shall survive the termination
of this Agreement.

      Section 6.08 Master Servicer Errors and Omissions Policy.

      The Master Servicer shall maintain, at all times and at its own
expense, a Master Servicer Errors and Omissions Policy, which policy shall
have such terms and coverage amounts as are comparable to those of errors and
omissions policies maintained by master servicers of mortgage loans generally.

      The Master Servicer Errors and Omissions Policy shall insure the Master
Servicer, its successors and assigns, against any losses resulting from
negligence, errors or omissions on the part of officers, employees or other
persons acting on behalf of the Master Servicer in the performance of its
duties as Master Servicer pursuant to this Agreement.

      The Master Servicer shall maintain in effect the Master Servicer Errors
and Omissions Policy at all times and the Master Servicer Errors and
Omissions Policy may not be canceled, permitted to lapse or otherwise
terminated without the acquisition of comparable coverage by the Master
Servicer.

                                   ARTICLE VII

                                     DEFAULT

      Section 7.01 Events of Default.

      In case one or more of the following Events of Default by the Master
Servicer shall occur and be continuing:

      (i) any failure by the Master Servicer to remit any funds to the Paying
   Agent as required by Section 4.03 continues unremedied for a period of
   three business days after either (a) receipt by the Master Servicer of
   written notice of such failure, requiring the same to be remedied, shall
   have been given to the Master Servicer by the Trustee or to the Master
   Servicer and the Trustee by the holders of Certificates evidencing in the
   aggregate not less than 25% of the aggregate Voting Interest represented
   by all Certificates or (b) solely in the case of the failure of the Master
   Servicer to remit any Periodic Advance required to be remitted pursuant to
   Section 3.03, the date upon which the Master Servicer delivered to the
   Trustee the certification required by Section 3.03(a);

      (ii) any failure on the part of the Master Servicer to observe or
   perform in any material respect any of its covenants or agreements under
   Sections 3.05, 3.11 or 3.12 hereof, subject to any cure period set forth
   in such sections;

      (iii) any failure on the part of the Master Servicer duly to observe or
   perform in any material respect any other of the covenants or agreements
   on the part of the Master Servicer in the Certificates or in this
   Agreement, which continues unremedied for a period of 60 days after the
   date on which written notice of such failure, requiring the same to be
   remedied, shall have been given to the Master Servicer by the Trustee or
   the Depositor, or to the Master Servicer and the Trustee by the holders of
   Certificates evidencing in the aggregate not less than 25% of the
   aggregate Voting Interest represented by all Certificates;

      (iv) a decree or order of a court or agency or supervisory authority
   having jurisdiction in the premises for the appointment of a trustee,
   conservator, receiver or liquidator in any bankruptcy, insolvency,
   readjustment of debt, marshaling of assets and liabilities or similar
   proceedings, or for the winding-up or liquidation of its affairs, shall
   have been entered against the Master Servicer and such decree or order
   shall have remained in force undischarged and unstayed for a period of 60
   days;

      (v) the Master Servicer shall consent to the appointment of a trustee,
   conservator, receiver or liquidator or liquidating committee in any
   bankruptcy, insolvency, readjustment of debt, marshaling of assets and
   liabilities, voluntary liquidation or similar proceedings of or relating
   to the Master Servicer, or of or relating to all or substantially all of
   its property;

      (vi) the Master Servicer shall admit in writing its inability to pay
   its debts generally as they become due, file a petition to take advantage
   of any applicable insolvency, bankruptcy or reorganization statute, make
   an assignment for the benefit of its creditors or voluntarily suspend
   payment of its obligations;

      (vii) the Master Servicer shall be dissolved, or shall dispose of all
   or substantially all of its assets; or consolidate with or merge into
   another entity or shall permit another entity to consolidate or merge into
   it, such that the resulting entity does not meet the criteria for a
   successor master servicer, as specified in Section 6.02 hereof; or

      (viii) the Master Servicer and any Subservicer appointed by it becomes
   ineligible to service for both Fannie Mae and Freddie Mac, which
   ineligibility continues unremedied for a period of 90 days;

then, and in each and every such case, subject to applicable law, so long as
an Event of Default shall not have been remedied, either the Trustee or the
holders of Certificates evidencing in the aggregate not less than 66 2/3% of
the aggregate Voting Interest represented by all Certificates, by notice in
writing to the Master Servicer (and to the Trustee if given by the
Certificateholders) may terminate all of the rights and obligations of the
Master Servicer under this Agreement and in and to the Mortgage Loans, but
without prejudice to any rights which the Master Servicer may have to the
aggregate Master Servicing Fees due prior to the date of transfer of the
Master Servicer's responsibilities hereunder, reimbursement of expenses to
the extent permitted by this Agreement, Periodic Advances and other advances
of its own funds. Upon receipt by the Master Servicer of such written notice,
all authority and power of the Master Servicer under this Agreement, whether
with respect to the Certificates or the Mortgage Loans or otherwise, shall
pass to and be vested in the Trustee pursuant to and under this Section,
subject to the provisions of Section 7.05; and, without limitation, the
Trustee is hereby authorized and empowered to execute and deliver, on behalf
of the Master Servicer, as attorney-in-fact or otherwise, any and all
documents and other instruments, and to do or accomplish all other acts or
things necessary or appropriate to effect the purposes of such notice of
termination, whether to complete the transfer and endorsement or assignment
of the Mortgage Loans and related documents or otherwise. The Master Servicer
agrees to cooperate with the Trustee in effecting the termination of the
Master Servicer's responsibilities and rights hereunder and shall promptly
provide the Trustee all documents and records reasonably requested by it to
enable it to assume the Master Servicer's functions hereunder and shall
promptly also transfer to the Trustee all amounts which then have been or
should have been deposited in the Certificate Account by the Master Servicer
or which are thereafter received by the Master Servicer with respect to the
Mortgage Loans.

      Section 7.02 Other Remedies of Trustee.

      During the continuance of any Event of Default, so long as such Event
of Default shall not have been remedied, the Trustee, in addition to the
rights specified in Section 7.01, shall have the right, in its own name as
trustee of an express trust, to take all actions now or hereafter existing at
law, in equity or by statute to enforce its rights and remedies and to
protect the interests, and enforce the rights and remedies, of the
Certificateholders (including the institution and prosecution of all
judicial, administrative and other proceedings and the filing of proofs of
claim and debt in connection therewith). Except as otherwise expressly
provided in this Agreement, no remedy provided for by this Agreement shall be
exclusive of any other remedy, and each and every remedy shall be cumulative
and in addition to any other remedy and no delay or omission to exercise any
right or remedy shall impair any such right or remedy or shall be deemed to
be a waiver of any Event of Default.

      Section 7.03 Directions by Certificateholders and Duties of Trustee
During Event of Default.

      During the continuance of any Event of Default, Holders of Certificates
evidencing in the aggregate not less than 25% of the aggregate Voting
Interest represented by all Certificates may direct the time, method and
place of conducting any proceeding for any remedy available to the Trustee,
or exercising any trust or power conferred upon the Trustee, under this
Agreement; provided, however, that the Trustee shall be under no obligation
to pursue any such remedy, or to exercise any of the rights or powers vested
in it by this agreement (including, without limitation, (i) the conducting or
defending of any administrative action or litigation hereunder or in relation
hereto and (ii) the terminating of the Master Servicer from its rights and
duties as servicer hereunder) at the request, order or direction of any of
the Certificateholders, unless such Certificateholders shall have offered to
the Trustee reasonable security or indemnity against the cost, expenses and
liabilities which may be incurred therein or thereby and, provided further,
that, subject to the provisions of Section 8.01, the Trustee shall have the
right to decline to follow any such direction if the Trustee, in accordance
with an Opinion of Counsel, determines that the action or proceeding so
directed may not lawfully be taken or if the Trustee in good faith determines
that the action or proceeding so directed would involve it in personal
liability or be unjustly prejudicial to the nonassenting Certificateholders.

      Section 7.04 Action upon Certain Failures of the Master Servicer and
upon Event of Default.

      In the event that the Trustee shall have knowledge of any failure of
the Master Servicer specified in Section 7.01(i), (ii) or (iii) which would
become an Event of Default upon the Master Servicer's failure to remedy the
same after notice, the Trustee may, but need not if the Trustee deems it not
in the Certificateholders' best interest, give notice thereof to the Master
Servicer; provided however that, without limiting any remedy as a result of
such failure, the Trustee shall be required to give notice thereof to the
Master Servicer in the case of the failure by the Master Servicer to observe
or perform any of its covenants under Sections 3.05, 3.11, 3.12, 6.02 or
6.06(b) of this Agreement. For all purposes of this Agreement, in the absence
of actual knowledge by a Responsible Officer of the Trustee, the Trustee
shall not be deemed to have knowledge of any failure of the Master Servicer
as specified in Section 7.01(i), (ii) and (iii) or any Event of Default
unless notified thereof in writing by the Master Servicer or by a
Certificateholder.

      Section 7.05 Trustee to Act; Appointment of Successor.

      When the Master Servicer receives notice of termination pursuant to
Section 7.01 or the Trustee receives the resignation of the Master Servicer
evidenced by an Opinion of Counsel pursuant to Section 6.04, the Trustee
shall be the successor in all respects to the Master Servicer in its capacity
as master servicer under this Agreement and the transactions set forth or
provided for herein and shall have the rights and powers and be subject to
all the responsibilities, duties and liabilities relating thereto placed on
the Master Servicer by the terms and provisions hereof and in its capacity as
such successor shall have the same limitation of liability herein granted to
the Master Servicer. In the event that the Trustee is succeeding to the
Master Servicer as the Master Servicer, as compensation therefor, the Trustee
shall be entitled to receive monthly such portion of the Master Servicing
Fee, together with such other master servicing compensation as is agreed to
at such time by the Trustee and the Master Servicer, but in no event more
than 25% thereof until the date of final cessation of the Master Servicer's
master servicing activities hereunder. Notwithstanding the above, the Trustee
may, if it shall be unwilling to so act, or shall, if it is unable to so act
or to obtain a qualifying bid as described below, appoint, or petition a
court of competent jurisdiction to appoint, any housing and home finance
institution, bank or mortgage servicing institution having a net worth of not
less than $10,000,000 and meeting such other standards for a successor master
servicer as are set forth herein, as the successor to the Master Servicer
hereunder in the assumption of all or any part of the responsibilities,
duties or liabilities of the Master Servicer hereunder; provided, however,
that until such a successor master servicer is appointed and has assumed the
responsibilities, duties and liabilities of the Master Servicer hereunder,
the Trustee shall continue as the successor to the Master Servicer as
provided above. Upon cessation of the Master Servicer's master servicing
activities hereunder, the Trustee or any other successor master servicer
shall be entitled to compensation not to exceed the compensation specified in
Section 6.05 hereof, which amount shall include compensation for acting as
paying agent. If the Master Servicer and the Paying Agent are not the same
party, the Master Servicer shall pay the compensation of the Paying Agent. In
the event the Trustee is required to solicit bids as provided above, the
Trustee shall solicit, by public announcement, bids from housing and home
finance institutions, banks and mortgage servicing institutions meeting the
qualifications set forth in the preceding sentence for the purchase of the
master servicing functions. Such public announcement shall specify that the
successor master servicer shall be entitled to the full amount of the Master
Servicing Fee as compensation together with the other master servicing
compensation in the form of late reporting fees or otherwise as provided in
Section 6.05, which amount shall include compensation for acting as paying
agent. Within 30 days after any such public announcement, the Trustee shall
negotiate and effect the sale, transfer and assignment of the master
servicing rights and responsibilities hereunder to the qualified party
submitting the highest qualifying bid. The Trustee shall deduct all costs and
expenses of any public announcement and of any sale, transfer and assignment
of the master servicing rights and responsibilities hereunder from any sum
received by the Trustee from the successor to the Master Servicer in respect
of such sale, transfer and assignment. After such deductions, the remainder
of such sum shall be paid by the Trustee to the Master Servicer at the time
of such sale, transfer and assignment to the Master Servicer's successor. The
Trustee and such successor shall take such action, consistent with this
Agreement, as shall be necessary to effectuate any such succession. The
Master Servicer agrees to cooperate with the Trustee and any successor master
servicer in effecting the termination of the Master Servicer's servicing
responsibilities and rights hereunder and shall promptly provide the Trustee
or such successor master servicer, as applicable, all documents and records
reasonably requested by it to enable it to assume the Master Servicer's
function hereunder and shall promptly also transfer to the Trustee or such
successor master servicer, as applicable, all amounts which then have been or
should have been deposited in the Certificate Account by the Master Servicer
or which are thereafter received by the Master Servicer with respect to the
Mortgage Loans. Neither the Trustee nor any other successor master servicer
shall be deemed to be in default hereunder by reason of any failure to make,
or any delay in making, any distribution hereunder or any portion thereof
caused by (i) the failure of the Master Servicer to deliver, or any delay in
delivering, cash, documents or records to it, or (ii) restrictions imposed by
any regulatory authority having jurisdiction over the Master Servicer.
Notwithstanding anything to the contrary contained in Section 7.01 above or
this Section 7.05, the Master Servicer shall retain all of its rights and
responsibilities hereunder, and no successor (including the Trustee) shall
succeed thereto, if the assumption thereof by such successor would cause the
rating assigned to any Certificates to be revoked, downgraded or placed on
credit review status (other than for possible upgrading) by either Rating
Agency and the retention thereof by the Master Servicer would avert such
revocation, downgrading or review.

      All costs associated with the appointment of a successor master
servicer, to the extent not deducted from any sum received by the Trustee
from the successor master servicer, shall be paid to the Person that incurred
them by the predecessor master servicer. Without limiting the predecessor
master servicer's obligation, if the predecessor master servicer fails to pay
such costs, such costs shall be reimbursed by the Trust.

      The predecessor Master Servicer and successor Master Servicer shall notify
the Depositor and Trustee of any such appointment at least two Business Days
prior to the effective date thereof and shall provide the Depositor and the
Trustee with all information required by the Depositor to comply with its
reporting obligation under Item 6.02 of Form 8-K not later than the effective
date of such appointment and the successor Master Servicer shall report such
event on Form 8-K within four business days of the occurrence of such event.

      Section 7.06 Notification to Certificateholders.

      Upon any termination of the Master Servicer or appointment of a
successor master servicer, in each case as provided herein, the Trustee shall
give prompt written notice thereof to Certificateholders at their respective
addresses appearing in the Certificate Register. The Trustee shall also,
within 45 days after the occurrence of any Event of Default known to the
Trustee, give written notice thereof to Certificateholders at their
respective addresses appearing in the Certificate Register, unless such Event
of Default shall have been cured or waived within said 45 day period.

                                  ARTICLE VIII

                             CONCERNING THE TRUSTEE

      Section 8.01 Duties of Trustee.

      The Trustee, prior to the occurrence of an Event of Default of which a
Responsible Officer of the Trustee shall have actual knowledge and after the
curing of all Events of Default which may have occurred, undertakes to
perform such duties and only such duties as are specifically set forth in
this Agreement. In case an Event of Default of which a Responsible Officer of
the Trustee shall have actual knowledge has occurred (which has not been
cured), the Trustee, subject to the provisions of Sections 7.01, 7.03, 7.04
and 7.05, shall exercise such of the rights and powers vested in it by this
Agreement, and use the same degree of care and skill in its exercise as a
prudent person would exercise or use under the circumstances in the conduct
of such person's own affairs.

      The Trustee, upon receipt of all resolutions, certificates, statements,
opinions, reports, documents, orders or other instruments furnished to the
Trustee, which are specifically required to be furnished pursuant to any
provision of this Agreement, shall examine them to determine whether they are
in the form required by this Agreement; provided, however, that the Trustee
shall not be responsible for the accuracy or content of any certificate,
statement, instrument, report, notice or other document furnished by the
Master Servicer or the Servicers hereunder.

      No provision of this Agreement shall be construed to relieve the
Trustee from liability for its own negligent action, its own negligent
failure to act or its own willful misconduct; provided, however, that:

      (i) Prior to the occurrence of an Event of Default of which a
   Responsible Officer of the Trustee shall have actual knowledge and after
   the curing of all such Events of Default which may have occurred, the
   duties and obligations of the Trustee shall be determined solely by the
   express provisions of this Agreement, the Trustee shall not be liable
   except for the performance of such duties and obligations as are
   specifically set forth in this Agreement, no implied covenants or
   obligations shall be read into this Agreement against the Trustee and, in
   the absence of bad faith on the part of the Trustee, the Trustee may
   conclusively rely, as to the truth of the statements and the correctness
   of the opinions expressed therein, upon any certificates or opinions
   furnished to the Trustee, and conforming to the requirements of this
   Agreement;

      (ii) The Trustee shall not be personally liable with respect to any
   action taken, suffered or omitted to be taken by it in good faith in
   accordance with the direction of holders of Certificates which evidence in
   the aggregate not less than 25% of the Voting Interest represented by all
   Certificates relating to the time, method and place of conducting any
   proceeding for any remedy available to the Trustee, or exercising any
   trust or power conferred upon the Trustee, under this Agreement;

      (iii) The Trustee shall not be liable for any error of judgment made in
   good faith by any of its Responsible Officers, unless it shall be proved
   that the Trustee or such Responsible Officer, as the case may be, was
   negligent in ascertaining the pertinent facts; and

      (iv) The Trustee shall not be required to take notice or be deemed to
   have notice or knowledge of any default or Event of Default unless a
   Responsible Officer of the Trustee shall have received written notice or
   obtained actual knowledge thereof. In absence of such notice or actual
   knowledge, the Trustee may conclusively assume that there is no default or
   Event of Default.

      None of the provisions contained in this Agreement shall require the
Trustee to expend or risk its own funds or otherwise incur personal financial
liability in the performance of any of its duties hereunder or in the
exercise of any of its rights or powers if there is reasonable ground for
believing that repayment of such funds or adequate indemnity against such
risk or liability is not reasonably assured to it.

      Section 8.02 Certain Matters Affecting the Trustee.

      Except as otherwise provided in Section 8.01:

      (i) The Trustee may request and rely and shall be protected in acting
   or refraining from acting upon any resolution, Officer's Certificate,
   certificate of auditors or any other certificate, statement, instrument,
   opinion, report, notice, request, consent, order, appraisal, bond or other
   paper or document believed by it to be genuine and to have been signed or
   presented by the proper party or parties and the manner of obtaining
   consents and evidencing the authorization of the execution thereof shall
   be subject to such reasonable regulations as the Trustee may prescribe;

      (ii) The Trustee may consult with counsel, and any advice of such
   counsel or any Opinion of Counsel shall be full and complete authorization
   and protection in respect of any action taken or suffered or omitted by it
   hereunder in good faith and in accordance with such advice or Opinion of
   Counsel;

      (iii) The Trustee shall not be personally liable for any action taken,
   suffered or omitted by it in good faith and believed by it to be
   authorized or within the discretion or rights or powers conferred upon it
   by this Agreement;

      (iv) Subject to Section 7.04, the Trustee shall not be accountable,
   shall have no liability and makes no representation as to any acts or
   omissions hereunder of the Master Servicer until such time as the Trustee
   may be required to act as Master Servicer pursuant to Section 7.05 and
   thereupon only for the acts or omissions of the Trustee as successor
   Master Servicer;

      (v) The Trustee may execute any of the trusts or powers hereunder or
   perform any duties hereunder either directly or by or through agents or
   attorneys and the Trustee shall not be responsible for any misconduct or
   negligence on the part of such agent or attorney appointed by any other
   party to this Agreement, including without limitation, the appointment of
   any custodian;

      (vi) The Trustee shall be under no obligation to exercise any of the
   trusts or powers vested in it by the Agreement, conduct or defend any
   litigation hereunder or in relation hereto at the request, order or
   direction of any of the Certificateholders, pursuant to the provisions of
   this Agreement, unless such Certificateholders shall have offered to the
   Trustee security or indemnity satisfactory to the Trustee against the
   costs, expenses and liabilities which may be incurred therein or herein
   (which in the case of Certificateholders representing in the aggregate not
   less than 66-2/3% of the aggregate Voting Interests will be deemed
   satisfied by a letter agreement with respect to such costs from such
   Certificateholders);

      (vii) The right of the Trustee to perform any discretionary act
   enumerated in this Agreement shall not be construed as a duty, and the
   Trustee shall not be answerable for other than its negligence of willful
   misconduct in the performance of such act; and

      (viii) The Trustee shall not be required to give any bond or surety in
   respect of the execution of the Trust Estate created hereby or the powers
   granted hereunder.

      Section 8.03 Trustee Not Required to Make Investigation.

      Prior to the occurrence of an Event of Default of which a Responsible
Officer of the Trustee shall have actual knowledge hereunder and after the
curing of all Events of Default which may have occurred, the Trustee shall
not be bound to make any investigation into the facts or matters stated in
any resolution, certificate, statement, instrument, opinion, report, notice,
request, consent, order, appraisal, bond, Mortgage, Mortgage Note or other
paper or document (provided the same appears regular on its face), unless
requested in writing to do so by holders of Certificates evidencing in the
aggregate not less than 51% of the Voting Interest represented by all
Certificates; provided, however, that if the payment within a reasonable time
to the Trustee of the costs, expenses or liabilities likely to be incurred by
it in the making of such investigation is, in the opinion of the Trustee, not
reasonably assured to the Trustee by the security afforded to it by the terms
of this Agreement, the Trustee may require indemnity reasonably satisfactory
to the Trustee against such cost, expense or liability as a condition to so
proceeding. The reasonable expense of every such investigation shall be paid
by the Master Servicer or, if paid by the Trustee shall be repaid by the
Master Servicer upon demand from the Master Servicer's own funds.

      Section 8.04 Trustee Not Liable for Certificates or Mortgage Loans.

      The recitals contained herein and in the Certificates shall be taken as
the statements of the Depositor, and the Trustee assumes no responsibility as
to the correctness of the same. The Trustee makes no representation for the
correctness of the same. The Trustee makes no representation as to the
validity or sufficiency of this Agreement or of the Certificates or of any
Mortgage Loan or related document. Subject to Section 2.04, the Trustee shall
not be accountable for the use or application by the Depositor of any of the
Certificates or of the proceeds of such Certificates, or for the use or
application of any funds paid to the Master Servicer in respect of the
Mortgage Loans deposited in or withdrawn from the Certificate Account by the
Master Servicer or, in its capacity as trustee, for investment of any such
amounts.

      Section 8.05 Trustee May Own Certificates.

      The Trustee, and any agent thereof, in its individual or any other
capacity, may become the owner or pledgee of Certificates with the same
rights it would have if it were not Trustee or such agent and may transact
banking and/or trust business with the Depositor, the Master Servicer or
their affiliates.

      Section 8.06 The Master Servicer to Pay Fees and Expenses; Limitation
on Liability.

      The Master Servicer covenants and agrees to pay to the Trustee from
time to time, from its own funds, and the Trustee shall be entitled to
receive, reasonable compensation (which shall not be limited by any provision
of law in regard to the compensation of a trustee of an express trust, but
which shall not include the initial acceptance and/or legal fee of the
Trustee which shall be paid by the Depositor) for all services rendered by it
in the execution of the trusts hereby created and in the exercise and
performance of any of the powers and duties hereunder of the Trustee.

      In addition, except as otherwise agreed upon in writing by the Master
Servicer and the Trustee, the Trust shall reimburse the Trustee for all
reasonable expenses, disbursements and advances incurred or made by the
Trustee in accordance with any of the provisions of this Agreement to the
extent permitted by Treasury Regulations Section 1.860G-1(b)(3), except for
(i) any such expense, disbursement or advance arising from the Trustee's
gross negligence, bad faith or willful misconduct and (ii) any routine
ongoing expenses incurred by the Trustee in the ordinary course of its duties
as Trustee hereunder or for any other expenses.

      The Trustee and any director, officer, employee or agent of the Trustee
shall be entitled to indemnification by the Trust Estate and held harmless
against any loss, liability or expense (including reasonable attorney's fees)
(a) incurred in connection with any claim or legal action relating to
(i) this Agreement, (ii) the Certificates, or (iii) the performance of any of
the Trustee's duties under this Agreement, unless the loss, liability or
expense was incurred by reason of willful misfeasance, bad faith or gross
negligence in the performance of any of the Trustee's duties under this
Agreement and (b) resulting from any tax or information return which was
prepared by, or should have been prepared by, the applicable Servicer or
Master Servicer.

      The obligations of the Trust Estate under this Section 8.06 shall
survive the resignation and removal of the Trustee and payment of the
Certificates.

      Section 8.07 Eligibility Requirements.

      The Trustee hereunder shall at all times (i) be a corporation or
association having its principal office in a state and city acceptable to the
Depositor, organized and doing business under the laws of such state or the
United States of America, authorized under such laws to exercise corporate
trust powers, having a combined capital and surplus of at least $50,000,000,
or shall be a member of a bank holding system, the aggregate combined capital
and surplus of which is at least $50,000,000, provided that its separate
capital and surplus shall at all times be at least the amount specified in
Section 310(a)(2) of the Trust Indenture Act of 1939, (ii) be subject to
supervision or examination by federal or state authority and (iii) have a
credit rating or be otherwise acceptable to the Rating Agencies such that
neither of the Rating Agencies would reduce their respective then current
ratings of the Certificates (or have provided such security from time to time
as is sufficient to avoid such reduction) as evidenced in writing by each
Rating Agency. If such corporation or association publishes reports of
condition at least annually, pursuant to law or to the requirements of the
aforesaid supervising or examining authority, then for the purposes of this
Section the combined capital and surplus of such corporation or association
shall be deemed to be its combined capital and surplus as set forth in its
most recent report of condition so published. In case at any time the Trustee
shall cease to be eligible in accordance with the provisions of this Section,
the Trustee shall resign immediately in the manner and with the effect
specified in Section 8.08.

      Section 8.08 Resignation and Removal.

      The Trustee may at any time resign and be discharged from the trust
hereby created by giving written notice of resignation to the Master
Servicer, such resignation to be effective upon the appointment of a
successor trustee. Upon receiving such notice of resignation, the Master
Servicer shall promptly appoint a successor trustee by written instrument, in
duplicate, one copy of which instrument shall be delivered to the resigning
entity and one copy to its successor. If no successor trustee shall have been
appointed and have accepted appointment within 30 days after the giving of
such notice of resignation, the resigning Trustee may petition any court of
competent jurisdiction for the appointment of a successor trustee.

      If at any time the Trustee shall cease to be eligible in accordance
with the provisions of Section 8.07 and shall fail to resign after written
request for its resignation by the Master Servicer, or if at any time the
Trustee shall become incapable of acting, or an order for relief shall have
been entered in any bankruptcy or insolvency proceeding with respect to such
entity, or a receiver of such entity or of its property shall be appointed,
or any public officer shall take charge or control of the Trustee or of the
property or affairs of the Trustee for the purpose of rehabilitation,
conversion or liquidation, or the Master Servicer shall deem it necessary in
order to change the situs of the Trust Estate for state tax reasons, then the
Master Servicer shall remove the Trustee and appoint a successor trustee by
written instrument, in duplicate, one copy of which instrument shall be
delivered to the Trustee so removed and one copy to the successor trustee.

      In addition, if (a) the Trustee fails to comply with its obligations to
deliver any assessment of servicing compliance or registered public
accounting firm attestation reports required pursuant to Section 3.11 or (b)
any Servicing Function Participant engaged by the Trustee fails to comply
with its obligations to deliver any assessment of servicing compliance or
registered public accounting firm attestation reports, the Master Servicer,
may, after consultation with the Depositor, remove the Trustee and appoint a
successor trustee by written instrument, in duplicate, one copy of which
instrument shall be delivered to the Trustee so removed and one copy to the
successor trustee.

      The Holders of Certificates evidencing in the aggregate not less than
51% of the Voting Interests represented by all Certificates (except that any
Certificate registered in the name of the Depositor, the Master Servicer or
any affiliate thereof will not be taken into account in determining whether
the requisite Voting Interests has been obtained) may at any time remove the
Trustee and appoint a successor by written instrument or instruments, in
triplicate, signed by such holders or their attorneys-in-fact duly
authorized, one complete set of which instruments shall be delivered to the
Master Servicer, one complete set of which shall be delivered to the entity
or entities so removed and one complete set of which shall be delivered to
the successor so appointed.

      Any resignation or removal of the Trustee and appointment of a
successor pursuant to any of the provisions of this Section shall become
effective upon acceptance of appointment by the successor as provided in
Section 8.09.

      Section 8.09 Successor.

      Any successor trustee appointed as provided in Section 8.08 shall
execute, acknowledge and deliver to the Master Servicer and to its
predecessor trustee an instrument accepting such appointment hereunder, and
thereupon the resignation or removal of the predecessor trustee shall become
effective, and such successor, without any further act, deed or reconveyance,
shall become fully vested with all the rights, powers, duties and obligations
of its predecessor hereunder, with like effect as if originally named as
trustee herein. The predecessor trustee shall deliver to its successor all
documents and statements held by it hereunder, and the Depositor, the Master
Servicer and the predecessor entity shall execute and deliver such
instruments and do such other things as may reasonably be required for more
fully and certainly vesting and confirming in the successor trustee all such
rights, powers, duties and obligations.

      If the predecessor trustee has resigned, or has been removed for cause,
all costs associated with the appointment of a successor trustee shall be
paid to the Person that incurred them by the predecessor trustee. Without
limiting the predecessor trustee's obligation, if the predecessor trustee
fails to pay such costs, such costs shall be reimbursed by the Trust;
provided however, that if the predecessor trustee has been terminated without
cause pursuant to Section 8.08, all reasonable expenses incurred in complying
with this Section 8.09 shall be reimbursed by the Trust to the Person that
incurred them.

      No successor shall accept appointment as provided in this Section
unless at the time of such acceptance such successor shall be eligible under
the provisions of Section 8.07.

      Upon acceptance of appointment by a successor as provided in this
Section, the successor trustee shall mail notice of the succession of such
trustee hereunder to all Holders of Certificates at their addresses as shown
in the Certificate Register.

      Section 8.10 Merger or Consolidation.

      Any Person into which the Trustee may be merged or converted or with
which it may be consolidated, to which it may sell or transfer its corporate
trust business and assets as a whole or substantially as a whole or any
Person resulting from any merger, sale, transfer, conversion or consolidation
to which the Trustee shall be a party, or any Person succeeding to the
business of such entity, shall be the successor of the Trustee hereunder;
provided, however, that (i) such Person shall be eligible under the
provisions of Section 8.07, without the execution or filing of any paper or
any further act on the part of any of the parties hereto, anything herein to
the contrary notwithstanding and (ii) the Trustee and such successor or
surviving Person shall notify the Depositor and the Master Servicer of any
such merger, conversion or consolidation at least two Business Days prior to
the effective date thereof and shall provide the Depositor and the Master
Servicer with all information required by the Depositor to comply with its
reporting obligations under Item 6.02 of Form 8-K not later than the
effective date of such merger, conversion or consolidation and the Master
Servicer shall report such event on Form 8-K within four business days of the
occurrence of such event.

      Section 8.11 Authenticating Agent.

      The Trustee may appoint an Authenticating Agent, which shall be
authorized to act on behalf of the Trustee in authenticating Certificates.
Wherever reference is made in this Agreement to the authentication of
Certificates by the Trustee or the Trustee's countersignature, such reference
shall be deemed to include authentication on behalf of the Trustee by the
Authenticating Agent and a certificate of authentication executed on behalf
of the Trustee by the Authenticating Agent. The Authenticating Agent must be
acceptable to the Depositor and the Master Servicer and must be a corporation
organized and doing business under the laws of the United States of America
or of any state, having a principal office and place of business in a state
and city acceptable to the Depositor and the Master Servicer, having a
combined capital and surplus of at least $15,000,000, authorized under such
laws to do a trust business and subject to supervision or examination by
federal or state authorities.

      Any corporation into which the Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which the Authenticating
Agent shall be a party, or any corporation succeeding to the corporate agency
business of the Authenticating Agent, shall be the Authenticating Agent
without the execution or filing of any paper or any further act on the part
of the Trustee or the Authenticating Agent.

      The Authenticating Agent may at any time resign by giving at least
30 days' advance written notice of resignation to the Trustee, the Depositor
and the Master Servicer. Except with respect to Wells Fargo Bank, for so long
as Wells Fargo Bank is acting as the Master Servicer, the Trustee may at any
time terminate the agency of the Authenticating Agent by giving written
notice thereof to the Authenticating Agent, the Depositor and the Master
Servicer. Upon receiving a notice of resignation or upon such a termination,
or in case at any time the Authenticating Agent shall cease to be eligible in
accordance with the provisions of this Section 8.11, the Trustee promptly
shall appoint a successor Authenticating Agent, which shall be acceptable to
the Master Servicer, and shall give written notice of such appointment to the
Depositor, and shall mail notice of such appointment to all
Certificateholders. Any successor Authenticating Agent upon acceptance of its
appointment hereunder shall become vested with all the rights, powers, duties
and responsibilities of its predecessor hereunder, with like effect as if
originally named as Authenticating Agent herein. No successor Authenticating
Agent shall be appointed unless eligible under the provisions of this
Section 8.11.

      The Authenticating Agent shall have no responsibility or liability for
any action taken by it as such at the direction of the Trustee. Any
reasonable compensation paid to the Authenticating Agent shall be payable by
the Master Servicer.

      Section 8.12 Separate Trustees and Co-Trustees.

      The Trustee shall have the power from time to time to appoint one or
more persons or corporations to act either as co-trustees jointly with the
Trustee, or as separate trustees, for the purpose of holding title to,
foreclosing or otherwise taking action with respect to any Mortgage Loan
outside the state where the Trustee has its principal place of business,
where such separate trustee or co-trustee is necessary or advisable (or the
Trustee is advised by the Master Servicer that such separate trustee or
co-trustee is necessary or advisable) under the laws of any state in which a
Mortgaged Property is located or for the purpose of otherwise conforming to
any legal requirement, restriction or condition in any state in which a
Mortgaged Property is located or in any state in which any portion of the
Trust Estate is located. The Master Servicer shall advise the Trustee when,
in its good faith opinion, a separate trustee or co-trustee is necessary or
advisable as aforesaid. The separate trustees or co-trustees so appointed
shall be trustees for the benefit of all of the Certificateholders and shall
have such powers, rights and remedies as shall be specified in the instrument
of appointment; provided, however, that no such appointment shall, or shall
be deemed to, constitute the appointee an agent of the Trustee. The Depositor
and the Master Servicer shall join in any such appointment, but such joining
shall not be necessary for the effectiveness of such appointment.

      Every separate trustee and co-trustee shall, to the extent permitted by
law, be appointed and act subject to the following provisions and conditions:

      (i) all powers, duties, obligations and rights conferred upon the
   Trustee, in respect of the receipt, custody and payment of moneys shall be
   exercised solely by the Trustee;

      (ii) all other rights, powers, duties and obligations conferred or
   imposed upon the Trustee shall be conferred or imposed upon and exercised
   or performed by the Trustee and such separate trustee or co-trustee
   jointly, except to the extent that under any law of any jurisdiction in
   which any particular act or acts are to be performed (whether as Trustee
   hereunder or as successor to the Master Servicer hereunder) the Trustee
   shall be incompetent or unqualified to perform such act or acts, in which
   event such rights, powers, duties and obligations (including the holding
   of title to the Trust Estate or any portion thereof in any such
   jurisdiction) shall be exercised and performed by such separate trustee or
   co-trustee;

      (iii) no separate trustee or co-trustee hereunder shall be personally
   liable by reason of any act or omission of any other separate trustee or
   co-trustee hereunder; and

      (iv) the Trustee may at any time accept the resignation of or remove
   any separate trustee or co-trustee so appointed by it, if such resignation
   or removal does not violate the other terms of this Agreement.

      Any notice, request or other writing given to the Trustee shall be
deemed to have been given to each of the then separate trustees and
co-trustees, as effectively as if given to each of them. Every instrument
appointing any separate trustee, co-trustee, or custodian shall refer to this
Agreement and the conditions of this Article. Each separate trustee and
co-trustee, upon its acceptance of the trusts conferred, shall be vested with
the estates or property specified in its instrument of appointment, either
jointly with the Trustee, or separately, as may be provided therein, subject
to all the provisions of this Agreement, specifically including every
provision of this Agreement relating to the conduct of, affecting the
liability of, or affording protection to, the Trustee. Every such instrument
shall be furnished to the Trustee.

      Any separate trustee, co-trustee, or custodian may, at any time,
constitute the Trustee, its agent or attorney-in-fact, with full power and
authority, to the extent not prohibited by law, to do any lawful act under or
in respect of this Agreement on its behalf and in its name. If any separate
trustee or co-trustee shall die, become incapable of acting, resign or be
removed, all of its estates, properties, rights, remedies and trusts shall
vest in and be exercised by the Trustee to the extent permitted by law,
without the appointment of a new or successor trustee.

      No separate trustee or co-trustee hereunder shall be required to meet
the terms of eligibility as a successor trustee under Section 8.07 hereunder
and no notice to Certificateholders of the appointment thereof shall be
required under Section 8.09 hereof.

      The Trustee agrees to instruct its co-trustees, if any, to the extent
necessary to fulfill such entity's obligations hereunder.

      The fees of any co-trustee whose appointment is necessary or advisable for
(i) conforming to any legal requirement, restriction or condition in any state
in which any Mortgaged Property or any portion of the Trust Estate is located,
will be paid by the Master Servicer, without reimbursement from the Trust and
(ii) any reason other than contemplated by clause (i), will be paid by the
Trustee, without reimbursement from the Trust. Expenses will be reimbursable to
the co-trustees to the extent, and in accordance with the standards, specified
in Section 8.06 hereof.

      Section 8.13 Tax Matters; Compliance with REMIC Provisions.

      (a) Each of the Trustee and the Master Servicer covenants and agrees
that it shall perform its duties hereunder in a manner consistent with the
REMIC Provisions and shall not knowingly take any action or fail to take any
other action that would (i) affect the determination of the REMIC's status as
a REMIC; or (ii) cause the imposition of any federal, state or local income,
prohibited transaction, contribution or other tax on either the REMIC or the
Trust Estate. The Master Servicer, or, in the case of any tax return or other
action required by law to be performed directly by the Trustee, the Trustee,
shall (i) prepare or cause to be prepared, timely cause to be signed by the
Trustee and file or cause to be filed annual federal and applicable state and
local income tax returns for the REMIC using a calendar year as the taxable
year and the accrual method of accounting; (ii) in the first such federal tax
return, make, or cause to be made, an election satisfying the requirements of
the REMIC Provisions, on behalf of the Trust Estate, to treat the REMIC as a
REMIC; (iii) prepare, execute and forward, or cause to be prepared, executed
and forwarded, to the Certificateholders all information reports or tax
returns required with respect to the Trust Estate, as and when required to be
provided to the Certificateholders, and to the Internal Revenue Service and
any other relevant governmental taxing authority in accordance with the REMIC
Provisions and any other applicable federal, state or local laws, including
without limitation information reports relating to "original issue discount"
and "market discount" as defined in the Code based upon the issue prices,
prepayment assumption and cash flows provided by the Depositor to the Master
Servicer and calculated on a monthly basis by using the issue prices of the
Certificates; (iv) make available information necessary for the application
of any tax imposed on transferors of residual interests to "disqualified
organizations" (as defined in the REMIC Provisions); (v) file Form 8811 and
apply for an Employee Identification Number with a Form SS-4 or any other
permissible method and respond to inquiries by Certificateholders or their
nominees concerning information returns, reports or tax returns; (vi)
maintain (or cause to be maintained by the Servicers) such records relating
to the REMIC, including but not limited to the income, expenses, individual
Mortgage Loans (including REO Mortgage Loans), other assets and liabilities
of the REMIC, and the fair market value and adjusted basis of the property of
the REMIC determined at such intervals as may be required by the Code, as may
be necessary to prepare the foregoing returns or information reports; (vii)
exercise reasonable care not to allow the creation of any "interests" in the
REMIC within the meaning of Code Section 860D(a)(2) other than the interests
in the REMIC represented by the Class A-2, Class A-3, Class A-PO, Class B-1,
Class B-2, Class B-3, Class B-4, Class B-5 and Class B-6 Certificates and the
Class A-R Certificate; (viii) exercise reasonable care not to allow the
occurrence of any "prohibited transactions" within the meaning of Code
Section 860F(a), unless the Master Servicer shall have provided an Opinion of
Counsel to the Trustee that such occurrence would not (a) result in a taxable
gain, (b) otherwise subject either of the REMIC or the Trust Estate to tax or
(c) cause the REMIC to fail to qualify as a REMIC; (ix) exercise reasonable
care not to allow the REMIC to receive income from the performance of
services or from assets not permitted under the REMIC Provisions to be held
by a REMIC; and (x) pay (on behalf of the REMIC) the amount of any federal
income tax, including, without limitation, prohibited transaction taxes,
taxes on net income from foreclosure property, and taxes on certain
contributions to a REMIC after the Startup Day, imposed on the REMIC when and
as the same shall be due and payable (but such obligation shall not prevent
the Master Servicer or any other appropriate Person from contesting any such
tax in appropriate proceedings and shall not prevent the Master Servicer from
withholding or depositing payment of such tax, if permitted by law, pending
the outcome of such proceedings). The Master Servicer shall be entitled to be
reimbursed pursuant to Section 3.02 for any taxes paid by it pursuant to
clause (x) of the preceding sentence, except to the extent that such taxes
are imposed as a result of the bad faith, willful misfeasance or gross
negligence of the Master Servicer in the performance of its obligations
hereunder.

      In order to enable the Master Servicer or the Trustee, as the case may be,
to perform its duties as set forth above, the Depositor shall provide, or cause
to be provided, to the Master Servicer within ten days after the Closing Date
all information or data that the Master Servicer determines to be relevant for
tax purposes to the valuations and offering prices of the Certificates,
including, without limitation, the price, yield, prepayment assumption and
projected cash flows of each Class of Certificates and the Mortgage Loans in the
aggregate. Thereafter, the Depositor shall provide to the Master Servicer or the
Trustee, as the case may be, promptly upon request therefor, any such additional
information or data that the Master Servicer or the Trustee, as the case may be,
may from time to time request in order to enable the Master Servicer to perform
its duties as set forth above. The Depositor hereby indemnifies the Master
Servicer or the Trustee, as the case may be, for any losses, liabilities,
damages, claims or expenses of the Master Servicer or the Trustee arising from
any errors or miscalculations by the Master Servicer or the Trustee pursuant to
this Section that result from any failure of the Depositor to provide, or to
cause to be provided, accurate information or data to the Master Servicer or the
Trustee, as the case may be, on a timely basis. The Master Servicer hereby
indemnifies the Depositor and the Trustee for any losses, liabilities, damages,
claims or expenses of the Depositor or the Trustee arising from the Master
Servicer's willful misfeasance, bad faith or gross negligence in preparing any
of the federal, state and local tax returns of the REMIC as described above. In
the event that the Trustee prepares any of the federal, state and local tax
returns of the REMIC as described above, the Trustee hereby indemnifies the
Depositor and the Master Servicer for any losses, liabilities, damages, claims
or expenses of the Depositor or the Master Servicer arising from the Trustee's
willful misfeasance, bad faith or negligence in connection with such
preparation.

      (b) Notwithstanding anything in this Agreement to the contrary, each of
the Master Servicer and the Trustee shall pay from its own funds, without any
right of reimbursement therefor, the amount of any costs, liabilities and
expenses incurred by the Trust Estate (including, without limitation, any and
all federal, state or local taxes, including taxes imposed on "prohibited
transactions" within the meaning of the REMIC Provisions) if and to the
extent that such costs, liabilities and expenses arise from a failure of the
Master Servicer or the Trustee, respectively, to perform its obligations
under this Section 8.13.

      The Holder of the Residual Certificate is hereby designated as the "tax
matters person" for the REMIC within the meaning of Treasury Regulations Section
1.860F-4(d). The "tax matters person" shall have the same duties with respect to
the REMIC as those of a "tax matters partner" under Subchapter C of Chapter 63
of Subtitle F of the Code. By its acceptance of the Residual Certificate, such
Holder irrevocably appoints the Master Servicer (and the Master Servicer hereby
agrees to act) as agent to perform all of the duties of the "tax matters
person."

      Section 8.14 Monthly Advances.

      In the event that Wells Fargo Bank in its capacity as Servicer fails to
make a Periodic Advance required to be made pursuant to the Wells Fargo Bank
Servicing Agreement on or before the Distribution Date, the Trustee shall
make a Periodic Advance as required by Section 3.03 hereof; provided,
however, the Trustee shall not be required to make such Periodic Advances if
prohibited by law or if it determines that such Periodic Advance would be a
Nonrecoverable Advance. With respect to those Periodic Advances which should
have been made by Wells Fargo Bank, the Trustee shall be entitled, pursuant
to Section 3.02(a)(i), (ii) or (v) hereof, to be reimbursed from the
Certificate Account for Periodic Advances and Nonrecoverable Advances made by
it.

      Section 8.15 Indemnification of the Master Servicer and Depositor by
the Trustee.

      The Trustee shall indemnify and hold harmless the Master Servicer and
the Depositor and any director, officer or agent thereof against any loss,
liability or expense, including reasonable attorney's fees, arising out of,
in connection with or incurred by reason of willful misfeasance, bad faith or
negligence in the performance of duties of the Trustee or by reason of
reckless disregard of its obligation to deliver any information, report,
certification, accountants' letter or other material required to comply with
Regulation AB. Any payment pursuant to this Section made by the Trustee to
the Master Servicer or the Depositor shall be from such entity's own funds,
without reimbursement therefor. The provisions of this Section 8.15 shall
survive the termination of this Agreement.

      Notwithstanding anything in this Agreement to the contrary, in no event
shall the Trustee be liable for any special, indirect or consequential loss
or damage of any kind whatsoever (including but not limited to lost profits)
resulting from the Trustee's nonperformance of its duties or obligations to
deliver any information, report, certification, accountants' letter or other
material required to comply with Regulation AB, even if the Trustee has been
advised of the likelihood of such loss or damage and regardless of the form
of action.

      Section 8.16 Trustee Errors and Omissions Policy.

      The Trustee shall maintain, at all times and at its own expense, a
Trustee Errors and Omissions Policy, which policy shall have such terms and
coverage amounts as are comparable to those of errors and omissions policies
maintained by trustees generally.

      The Trustee Errors and Omissions Policy shall insure the Trustee, its
successors and assigns, against any losses resulting from negligence, errors
or omissions on the part of officers, employees or other persons acting on
behalf of the Trustee in the performance of its duties as Trustee pursuant to
this Agreement.

      The Trustee shall maintain in effect the Trustee Errors and Omissions
Policy at all times and the Trustee Errors and Omissions Policy may not be
canceled, permitted to lapse or otherwise terminated without thirty Business
Days' prior written notice by registered mail to the Master Servicer and the
Depositor.

                                   ARTICLE IX

                                   TERMINATION

      Section 9.01 Termination upon Purchase by the Depositor or Liquidation
of All Mortgage Loans.

      Subject to Section 9.02, the respective obligations and
responsibilities of the parties to this Agreement created hereby (other than
the obligation of the Paying Agent to make certain payments after the Final
Distribution Date to Certificateholders and the obligation of the Master
Servicer to send certain notices as hereinafter set forth and the tax
reporting obligations under Sections 4.05 and 8.13 hereof) shall terminate
upon the last action required to be taken by the Paying Agent on the Final
Distribution Date pursuant to this Article IX following the earlier of (i)
the purchase by the Depositor of all Mortgage Loans and all property acquired
in respect of any Mortgage Loan remaining in the Trust Estate at a price
equal to the sum of (x) 100% of the unpaid principal balance of each Mortgage
Loan (other than any REO Mortgage Loan) as of the Final Distribution Date,
(y) the fair market value of the Mortgaged Property related to any REO
Mortgage Loan, plus with respect to clauses (x) and (y) any accrued and
unpaid interest through the last day of the month preceding the month of such
purchase at the applicable Mortgage Interest Rate less any Fixed Retained
Yield on each Mortgage Loan (including any REO Mortgage Loan) and (z) any
Reimbursement Amount owed to the Trust pursuant to Section 2.03 and (ii) the
final payment or other liquidation (or any advance with respect thereto) of
the last Mortgage Loan remaining in the Trust Estate (including for this
purpose the discharge of any Mortgagor under a defaulted Mortgage Loan on
which a Servicer is not obligated to foreclose due to environmental
impairment) or the disposition of all property acquired upon foreclosure or
deed in lieu of foreclosure of any Mortgage Loan; provided, however, that in
no event shall the trust created hereby continue beyond the expiration of 21
years from the death of the last survivor of the descendants of Joseph P.
Kennedy, the late ambassador of the United States to the Court of St. James,
living on the date hereof.

      The right of the Depositor to purchase all the assets of the Trust
Estate pursuant to clause (i) of the preceding paragraph is subject to
Section 9.02 and conditioned upon (A) the Pool Scheduled Principal Balance of
the Mortgage Loans as of the Final Distribution Date being less than the
amount set forth in Section 11.21 and (B) the sum of clause (i)(x) and (y) of
the preceding paragraph being less than or equal to the aggregate fair market
value of the Mortgage Loans (other than any REO Mortgage Loans) and the
Mortgaged Properties related to the REO Mortgage Loans; provided, however,
that this clause (B) shall not apply to any purchase by the Depositor if, at
the time of the purchase, the Depositor is no longer subject to regulation by
the Office of the Comptroller of the Currency, the FDIC, the Federal Reserve
or the Office of Thrift Supervision. Fair market value for purposes of this
paragraph and the preceding paragraph will be determined by the Master
Servicer as of the close of business on the third Business Day next preceding
the date upon which notice of any termination is furnished to
Certificateholders pursuant to the third paragraph of this Section 9.01. In
the case of any purchase by the Depositor pursuant to said clause (i) of the
preceding paragraph, the Depositor shall give the Trustee, the Paying Agent
and Master Servicer notice of its intent to purchase the assets of the Trust
by the fifth day of the month of the Final Distribution Date or such later
date as shall be acceptable to the Trustee and Master Servicer. The Depositor
or Master Servicer shall in such case provide to the Trustee confirmation of
deposit of the purchase price and the Trustee or the Custodian shall,
promptly following payment of the purchase price and upon receipt from the
Master Servicer of a Request for Release, release to the Depositor the Owner
Mortgage Loan Files and Retained Mortgage Loan Files, if applicable,
pertaining to the Mortgage Loans being purchased.

      Notice of any termination, specifying the Final Distribution Date
(which shall be a date that would otherwise be a Distribution Date) upon
which the Certificateholders may surrender their Certificates to the Paying
Agent for payment of the final distribution and cancellation, shall be given
promptly by the Paying Agent by letter to Certificateholders and the Trustee
mailed not earlier than the 15th day of the month preceding the month of such
final distribution and not later than the twentieth day of the month of such
final distribution specifying (A) the Final Distribution Date upon which
final payment of the Certificates will be made upon presentation and
surrender of Certificates at the Corporate Trust Office of the Paying Agent
therein designated, (B) the amount of any such final payment and (C) that the
Record Date otherwise applicable to such Distribution Date is not applicable,
payments being made (except in the case of any Class A Certificate
surrendered on a prior Distribution Date) pursuant to Section 4.01 only upon
presentation and surrender of the Certificates at the Corporate Trust Office
of the Paying Agent therein specified. If the Depositor is exercising its
right to purchase, the Depositor shall deposit in the Certificate Account on
or before the Final Distribution Date in immediately available funds an
amount equal to the purchase price for the assets of the Trust Estate
computed as above provided. Failure to give notice of termination as
described herein shall not entitle a Certificateholder to any interest beyond
the interest payable on the Final Distribution Date.

      Upon presentation and surrender of the Certificates, the Paying Agent
shall distribute to Certificateholders on the Final Distribution Date in
proportion to their respective Percentage Interests an amount equal to (i) as
to the Classes of Class A Certificates (other than any Class of Exchangeable
Certificates), the respective Principal Balance together with any related
Class A Unpaid Interest Shortfall and one month's interest in an amount equal
to the respective Interest Accrual Amount, (ii) as to the Classes of Class B
Certificates, the respective Principal Balance together with any related
Class B Unpaid Interest Shortfall and one month's interest in an amount equal
to the respective Interest Accrual Amount and (iii) as to the Residual
Certificate, the amounts (other than amounts retained to meet claims), if
any, which remain on deposit in the Certificate Account after application
pursuant to clauses (i) and (ii) above and payment to the Master Servicer of
any amounts it is entitled as reimbursement or otherwise hereunder.
Outstanding Exchangeable Certificates shall be entitled to receive their
proportionate share of distributions allocated to their Related Exchangeable
REMIC Certificates as set forth in Section 4.01(g). Notwithstanding the
foregoing, if the price paid pursuant to clause (i) of the first paragraph of
this Section 9.01, after reimbursement to the Servicers, the Master Servicer
and the Trustee of any Periodic Advances, is insufficient to pay in full the
amounts set forth in clauses (i) and (ii) of this paragraph, then any
shortfall in the amount available for distribution to Certificateholders
shall be allocated in reduction of the amounts otherwise distributable on the
Final Distribution Date in the same manner as Realized Losses are allocated
pursuant to Sections 4.02(a) hereof. Such distribution on the Final
Distribution Date shall be in lieu of the distribution otherwise required to
be made on such Distribution Date in respect of each Class of Certificates.

      In the event that all of the Certificateholders shall not surrender
their Certificates for final payment and cancellation within three months
following the Final Distribution Date, the Paying Agent shall on such date
cause all funds, if any, in the Payment Account not distributed in final
distribution to Certificateholders to be withdrawn therefrom and credited to
the remaining Certificateholders by depositing such funds in a separate
escrow account for the benefit of such Certificateholders. The Paying Agent
shall give a second written notice to the remaining Certificateholders to
surrender their Certificates for cancellation and receive the final
distribution with respect thereto. If within three months after the second
notice all the Certificates shall not have been surrendered for cancellation,
the Paying Agent may take appropriate steps, or may appoint an agent to take
appropriate steps, to contact the remaining Certificateholders concerning
surrender of their Certificates, and the cost thereof shall be paid out of
the funds on deposit in such escrow account.

      Section 9.02 Additional Termination Requirements.

      In the event of a termination of the Trust Estate upon the exercise by
the Depositor of its purchase option as provided in Section 9.01, the Trust
Estate shall be terminated in accordance with the following additional
requirements, unless the Trustee and the Master Servicer have received an
Opinion of Counsel to the effect that any other manner of termination (i)
will constitute a "qualified liquidation" of the Trust Estate within the
meaning of Code Section 860F(a)(4)(A) and (ii) will not subject the REMIC to
federal tax or cause the REMIC to fail to qualify as a REMIC at any time that
any Certificates are outstanding:

      (i) The notice given by the Paying Agent under Section 9.01 shall
   provide that such notice constitutes the adoption of a plan of complete
   liquidation of the REMIC as of the date of such notice (or, if earlier,
   the date on which the first such notice is mailed to Certificateholders).
   The Master Servicer shall also specify such date in a statement attached
   to the final tax return of the REMIC; and

      (ii) At or after the time of adoption of such a plan of complete
   liquidation and at or prior to the Final Distribution Date, the Trustee
   shall sell all of the assets of the Trust Estate to the Depositor for cash
   at the purchase price specified in Section 9.01 and the Paying Agent shall
   distribute such cash within 90 days of such adoption in the manner
   specified in Section 9.01.

                                    ARTICLE X

                            MISCELLANEOUS PROVISIONS

      Section 10.01 Amendment.

      (a) This Agreement or the Custodial Agreement may be amended from time
to time by the Depositor, the Master Servicer and the Trustee without the
consent of any of the Certificateholders, (i) to cure any ambiguity or
mistake, (ii) to correct or supplement any provisions herein or therein which
may be inconsistent with any other provisions herein or therein or in the
related Prospectus, (iii) to modify, eliminate or add to any of its
provisions to such extent as shall be necessary to maintain the qualification
of the REMIC as a REMIC at all times that any Certificates are outstanding or
to avoid or minimize the risk of the imposition of any federal tax on the
Trust Estate or the REMIC pursuant to the Code that would be a claim against
the Trust Estate, provided that (a) the Trustee has received an Opinion of
Counsel to the effect that such action is necessary or desirable to maintain
such qualification or to avoid or minimize the risk of the imposition of any
such tax and (b) such action shall not, as evidenced by such Opinion of
Counsel, adversely affect in any material respect the interests of any
Certificateholder, (iv) to conform the obligations of the parties under this
Agreement, or to add obligations of the parties to this Agreement, if
necessary, to comply with the requirements of Regulation AB, (v) to change
the timing and/or nature of deposits into the Certificate Account provided
that such change shall not, as evidenced by an Opinion of Counsel, adversely
affect in any material respect the interests of any Certificateholder, (vi)
to modify, eliminate or add to the provisions of Section 5.02 or any other
provisions hereof restricting transfer of the Certificates, provided that the
Depositor for purposes of Section 5.02 has determined in its sole discretion
that any such modifications to this Agreement will neither adversely affect
the rating on the Certificates nor give rise to a risk that the REMIC or any
of the Certificateholders will be subject to a tax caused by a transfer to a
non-permitted transferee, (vii) prior to the initial transfer of any Class of
Class B Certificates by the Depositor or an affiliate of the Depositor to a
Person other than the Depositor or an affiliate of the Depositor following
the Closing Date, (a) to change the Denomination which constitutes a Single
Certificate for such Class, (b) to change such Class from Definitive
Certificates to Book-Entry Certificates or from Book-Entry Certificates to
Definitive Certificates and (c) to modify, eliminate or add to the provisions
of Section 5.02 restricting transfer of any Class of Class B Certificates and
(viii) to make any other provisions with respect to matters or questions
arising under this Agreement or such Custodial Agreement which shall not be
materially inconsistent with the provisions of this Agreement, provided that
such action shall not, as evidenced by an Opinion of Counsel, adversely
affect in any material respect the interests of any Certificateholder.
Notwithstanding the foregoing, any amendment pursuant to clause (v) or (viii)
shall not be deemed to adversely affect in any material respect the interest
of Certificateholders and no Opinion of Counsel to that effect shall be
required if the person requesting the amendment instead obtains a letter from
each Rating Agency stating that the amendment would not result in the
downgrading or withdrawal of the respective ratings then assigned to the
Certificates.

      This Agreement or the Custodial Agreement may also be amended from time
to time by the Depositor, the Master Servicer and the Trustee with the
consent of the Holders of Certificates evidencing in the aggregate not less
than 66-2/3% of the aggregate Voting Interests of each Class of Certificates
affected thereby, for the purpose of adding any provisions to or changing in
any manner or eliminating any of the provisions of this Agreement or such
Custodial Agreement or of modifying in any manner the rights of the Holders
of Certificates of such Class; provided, however, that no such amendment
shall (i) reduce in any manner the amount of, or delay the timing of,
payments received on Mortgage Loans which are required to be distributed on
any Certificate without the consent of the Holder of such Certificate, (ii)
adversely affect in any material respect the interest of the Holders of
Certificates of any Class in a manner other than as described in clause (i)
hereof without the consent of Holders of Certificates of such Class
evidencing, as to such Class, Voting Interests aggregating not less than
66-2/3% or (iii) reduce the aforesaid percentage of Certificates of any Class
the Holders of which are required to consent to any such amendment, without
the consent of the Holders of all Certificates of such Class then outstanding.

      Notwithstanding any contrary provision of this Agreement, the Trustee
shall not consent to any amendment to this Agreement, other than an amendment
pursuant to clause (vii) of the second preceding paragraph, unless it shall
have first received an Opinion of Counsel to the effect that such amendment
will not subject the REMIC to tax or cause the REMIC to fail to qualify as a
REMIC at any time that any Certificates are outstanding.

      Promptly after the execution of any amendment requiring the consent of
Certificateholders, the Trustee shall furnish written notification of the
substance of such amendment to each Certificateholder.

      It shall not be necessary for the consent of Certificateholders under
this Section 10.01(a) to approve the particular form of any proposed
amendment, but it shall be sufficient if such consent shall approve the
substance thereof. The manner of obtaining such consents and of evidencing
the authorization of the execution thereof by Certificateholders shall be
subject to such reasonable regulations as the Trustee may prescribe.

      The Trustee shall give prompt written notice to the Custodian of any
amendment or supplement to this Agreement and furnish the Custodian with
written copies thereof.

      (b) Notwithstanding any contrary provision of this Agreement, if any of
the Mortgage Loans are Type 2 Mortgage Loans, as indicated on the Mortgage
Loan Schedule, the Master Servicer may, from time to time, amend Schedule I
hereto without the consent of any Certificateholder or the Trustee; provided,
however, (i) that such amendment does not conflict with any provisions of the
related Servicing Agreement, (ii) that the related Servicing Agreement
provides for the remittance of each type of Unscheduled Principal Receipts
received by such Servicer during the Applicable Unscheduled Principal Receipt
Period (as so amended) related to each Distribution Date to the Master
Servicer no later than the 24th day of the month in which such Distribution
Date occurs and (iii) that such amendment is for the purpose of changing the
Applicable Unscheduled Principal Receipt Period for Type 2 Mortgage Loans to
a Mid-Month Receipt Period with respect to all Unscheduled Principal Receipts.

      Section 10.02 Recordation of Agreement.

      This Agreement (or an abstract hereof, if acceptable to the applicable
recording office) is subject to recordation in all appropriate public offices
for real property records in all the towns or other comparable jurisdictions
in which any or all of the Mortgaged Properties are situated, and in any
other appropriate public office or elsewhere, such recordation to be effected
by the Master Servicer and at its expense on direction by the Trustee, but
only upon direction accompanied by an Opinion of Counsel to the effect that
such recordation materially and beneficially affects the interests of the
Certificateholders.

      For the purpose of facilitating the recordation of this Agreement as
herein provided and for other purposes, this Agreement may be executed
simultaneously in any number of counterparts, each of which counterparts
shall be deemed to be an original, and such counterparts shall constitute but
one and the same instrument.

      Section 10.03 Limitation on Rights of Certificateholders.

      The death or incapacity of any Certificateholder shall not operate to
terminate this Agreement or the Trust Estate, nor entitle such
Certificateholder's legal representatives or heirs to claim an accounting or
take any action or proceeding in any court for a partition or winding up of
the Trust Estate, nor otherwise affect the rights, obligations and
liabilities of the parties hereto or any of them.

      Except as otherwise expressly provided herein, no Certificateholder,
solely by virtue of its status as a Certificateholder, shall have any right
to vote or in any manner otherwise control the operation and management of
the Trust Estate, or the obligations of the parties hereto, nor shall
anything herein set forth, or contained in the terms of the Certificates, be
construed so as to constitute the Certificateholders from time to time as
partners or members of an association, nor shall any Certificateholder be
under any liability to any third person by reason of any action taken by the
parties to this Agreement pursuant to any provision hereof.

      No Certificateholder, solely by virtue of its status as
Certificateholder, shall have any right by virtue or by availing of any
provision of this Agreement to institute any suit, action or proceeding in
equity or at law upon or under or with respect to this Agreement, unless such
Holder previously shall have given to the Trustee a written notice of default
and of the continuance thereof, as hereinbefore provided, and unless the
Holders of Certificates evidencing not less than 25% of the Voting Interest
represented by all Certificates shall have made written request upon the
Trustee to institute such action, suit or proceeding in its own name as
Trustee hereunder and shall have offered to the Trustee such reasonable
indemnity as it may require against the cost, expenses and liabilities to be
incurred therein or thereby, and the Trustee, for 60 days after its receipt
of such notice, request and offer of indemnity, shall have neglected or
refused to institute any such action, suit or proceeding; it being understood
and intended, and being expressly covenanted by each Certificateholder with
every other Certificateholder and the Trustee, that no one or more Holders of
Certificates shall have any right in any manner whatever by virtue or by
availing of any provision of this Agreement to affect, disturb or prejudice
the rights of the Holders of any other of such Certificates, or to obtain or
seek to obtain priority over or preference to any other such Holder, or to
enforce any right under this Agreement, except in the manner herein provided
and for the benefit of all Certificateholders. For the protection and
enforcement of the provisions of this Section, each and every
Certificateholder and the Trustee shall be entitled to such relief as can be
given either at law or in equity.

      Section 10.04 Governing Law; Jurisdiction.

      This Agreement shall be construed in accordance with the laws of the
State of New York (without regard to conflicts of laws principles), and the
obligations, rights and remedies of the parties hereunder shall be determined
in accordance with such laws.

      Section 10.05 Notices.

      Unless otherwise provided in this Agreement, all demands, notices and
communications hereunder shall be in writing and shall be deemed to have been
duly given if personally delivered at or mailed by certified or registered
mail, return receipt requested or by facsimile (i) in the case of the
Depositor, to Wells Fargo Asset Securities Corporation, 5325 Spectrum Drive,
Frederick, Maryland 21703, Attention: Vice President, Structured Finance or
such other address as may hereafter be furnished to the Master Servicer and
the Trustee in writing by the Depositor, (ii) in the case of the Master
Servicer, to Wells Fargo Bank, N.A., 9062 Old Annapolis Road, Columbia,
Maryland 21045-1951, Attention: Corporate Trust Services-WFMBS 2007-17;
facsimile: (410) 715-2380 or such other address as may hereafter be furnished
to the Depositor and the Trustee in writing by the Master Servicer and
(iii) in the case of the Trustee or the Paying Agent, to the Corporate Trust
Office, or such other address as may hereafter be furnished to the Depositor
and the Master Servicer in writing by the Trustee or the Paying Agent. Any
notice required or permitted to be mailed to a Certificateholder shall be
given by first class mail, postage prepaid, at the address of such Holder as
shown in the Certificate Register. Any notice mailed or transmitted within
the time prescribed in this Agreement shall be conclusively presumed to have
been duly given, whether or not the addressee receives such notice; provided,
however, that any demand, notice or communication to or upon the Depositor,
the Master Servicer or the Trustee shall not be effective until received.

      For all purposes of this Agreement, in the absence of actual knowledge
by an officer of the Master Servicer, the Master Servicer shall not be deemed
to have knowledge of any act or failure to act of any Servicer unless
notified thereof in writing by the Trustee, the applicable Servicer or a
Certificateholder.

      Section 10.06 Severability of Provisions.

      If any one or more of the covenants, agreements, provisions or terms of
this Agreement shall be for any reason whatsoever held invalid, then such
covenants, agreements, provisions or terms shall be deemed severable from the
remaining covenants, agreements, provisions or terms of this Agreement and
shall in no way affect the validity or enforceability of the other provisions
of this Agreement or of the Certificates or the rights of the Holders thereof.

      Section 10.07 Special Notices to Rating Agencies.

      (a) The Trustee shall give prompt notice to each Rating Agency of the
occurrence of any of the following events of which a Responsible Officer has
notice:

      (i) any amendment to this Agreement pursuant to Section 10.01(a);

      (ii) any assignment by the Master Servicer of its rights and delegation
   of its duties pursuant to Section 6.06;

      (iii) any resignation of the Master Servicer pursuant to Section 6.04;

      (iv) the occurrence of any of the Events of Default described in
   Section 7.01;

      (v) any notice of termination given to the Master Servicer pursuant to
   Section 7.01; or

      (vi) the appointment of any successor to the Master Servicer pursuant
   to Section 7.05.

      (b) The Paying Agent shall give prompt notice to each Rating Agency of
any sale or transfer of the Class B Certificates pursuant to Section 5.02 to
an affiliate of the Depositor.

      (c) The Paying Agent shall give prompt notice to each Rating Agency of
the making of a final payment pursuant to Section 9.01.

      (d) The Master Servicer shall give prompt notice to each Rating Agency
of the occurrence of any of the following events:

      (i) the resignation of the Custodian or the appointment of a successor
   Custodian pursuant to the Custodial Agreement;

      (ii) the resignation or removal of the Trustee pursuant to Section 8.08;

      (iii) the appointment of a successor trustee pursuant to Section 8.09;
   or

      (iv) the sale, transfer or other disposition in a single transaction of
   50% or more of the equity interests in the Master Servicer.

      (e) The Master Servicer shall deliver to each Rating Agency or
otherwise make available to each Rating Agency in a format acceptable to each
Rating Agency:

      (i) reports prepared pursuant to Section 3.05 and 3.11; and

      (ii) the Distribution Date Statements.

      (f) The Depositor shall give prompt notice to each Rating Agency of any
amendment to a Servicing Agreement that affects the ability of the Servicer
to modify a Mortgage Loan.

      Section 10.08 Covenant of Depositor.

      The Depositor shall not amend Article Third of its Certificate of
Incorporation without the prior written consent of each Rating Agency rating
the Certificates.

      Section 10.09 Recharacterization.

      The Parties intend the conveyance by the Depositor to the Trustee of
all of its right, title and interest in and to the Trust Estate pursuant to
this Agreement to constitute a purchase and sale and not a loan.
Notwithstanding the foregoing, to the extent that such conveyance is held not
to constitute a sale under applicable law, it is intended that this Agreement
shall constitute a security agreement under applicable law and that the
Depositor shall be deemed to have granted to the Trustee a first priority
security interest in all of the Depositor's right, title and interest in and
to the Trust Estate. The Depositor shall make the initial Uniform Commercial
Code filings and take action as shall be necessary to perfect such security
interest. The Master Servicer shall take all actions, including, without
limitation, filing any Uniform Commercial Code continuation statements, as
shall be necessary to maintain the perfection of such security interest.

      Section 10.10 Regulation AB Compliance; Intent of Parties;
Reasonableness.  The parties hereto acknowledge that interpretations of the
requirements of Regulation AB may change over time, whether due to
interpretive guidance provided by the Commission or its staff, consensus
among participants in the asset-backed securities markets, advice of counsel,
or otherwise, and agree to comply with requests made by the Depositor or the
Master Servicer in good faith for delivery of information under these
provisions on the basis of evolving interpretations of Regulation AB. In
connection with the Trust, the parties hereto shall cooperate fully with the
Master Servicer and the Depositor to deliver to the Master Servicer and/or
the Depositor, any and all statements, reports, certifications, records and
any other information available to such party and reasonably necessary in the
good faith determination of the Depositor or the Master Servicer to permit
the Depositor or the Master Servicer to comply with the provisions of
Regulation AB, together with such disclosures reasonably believed by the
Depositor or the Master Servicer to be necessary in order to effect such
compliance.

                                   ARTICLE XI

                             TERMS FOR CERTIFICATES

      Section 11.01 Cut-Off Date.

      The Cut-Off Date for the Certificates is December 1, 2007.

      Section 11.02 Cut-Off Date Aggregate Principal Balance.

      The Cut-Off Date Aggregate Principal Balance is $480,976,949.70.

      Section 11.03 Original Class A Percentage.

      The Original Class A Percentage is 95.94565485%.

      Section 11.04 Reserved.

      Section 11.05 Original Principal Balances or Maximum Initial Principal
Balances of the Classes of Class A Certificates.

      As to the following Classes of Class A Certificates (other than the
Classes of Exchangeable REMIC Certificates and Exchangeable Certificates),
the Principal Balance of such Class as of the Cut-Off Date and as to the
Classes of Exchangeable REMIC Certificates and Exchangeable Certificates, the
Maximum Initial Principal Balance of such Class as of the Cut-Off Date, as
follows:

                                                 Original
                       Class               Principal Balance or
                                        Maximum Initial Principal
                                                 Balance
            ---------------------------------------------------------
              Class A-1                            $460,999,000.00
              Class A-2                            $442,329,000.00
              Class A-3                             $18,670,000.00
              Class A-PO                               $497,556.00
              Class A-R                                    $100.00

      Section 11.06 Original Aggregate Non-PO Principal Balance.

      The Original Aggregate Non-PO Principal Balance is $480,479,392.00.

      Section 11.07 Original Class B Principal Balance.

      The Original Class B Principal Balance is $19,480,292.00.

      Section 11.08 Original Principal Balances of the Classes of Class B
Certificates.

      As to the following Classes of Class B Certificates, the Principal
Balance of such Class as of the Cut-Off Date, is as follows:

                                             Original
                        Class            Principal Balance
                        -----            -----------------
                       Class B-1               $9,620,000.00
                       Class B-2               $3,848,000.00
                       Class B-3               $1,443,000.00
                       Class B-4               $2,404,000.00
                       Class B-5                 $722,000.00
                       Class B-6               $1,443,292.00

      Section 11.09 Original Class B-1 Fractional Interest.

      The Original Class B-1 Fractional Interest is 2.05217812%.

      Section 11.10 Original Class B-2 Fractional Interest.

      The Original Class B-2 Fractional Interest is 1.25131131%.

      Section 11.11 Original Class B-3 Fractional Interest.

      The Original Class B-3 Fractional Interest is 0.95098625%.

      Section 11.12 Original Class B-4 Fractional Interest.

      The Original Class B-4 Fractional Interest is 0.45065262%.

      Section 11.13 Original Class B-5 Fractional Interest.

      The Original Class B-5 Fractional Interest is 0.30038603%.

      Section 11.14 Original Class B-1 Percentage.

      The Original Class B-1 Percentage is 2.00216703%.

      Section 11.15 Original Class B-2 Percentage.

      The Original Class B-2 Percentage is 0.80086681%.

      Section 11.16 Original Class B-3 Percentage.

      The Original Class B-3 Percentage is 0.30032505%.

      Section 11.17 Original Class B-4 Percentage.

      The Original Class B-4 Percentage is 0.50033363%.

      Section 11.18 Original Class B-5 Percentage.

      The Original Class B-5 Percentage is 0.15026659%.

      Section 11.19 Original Class B-6 Percentage.

      The Original Class B-6 Percentage is 0.30038603%.

      Section 11.20 Closing Date.

      The Closing Date is December 20, 2007.

      Section 11.21 Right to Purchase.

      The right of the Depositor to purchase all of the Mortgage Loans
pursuant to Section 9.01 hereof shall be conditioned upon the Pool Scheduled
Principal Balance of the Mortgage Loans being less than $48,097,694.97 (10%
of the Cut-Off Date Aggregate Principal Balance) at the time of any such
purchase.

      Section 11.22 Single Certificate.

      A Single Certificate for the Class A-1 and Class A-2 Certificates
represents a $25,000 Denomination. A Single Certificate for the Class A-3,
Class A-PO, Class B-1, Class B-2 and Class B-3 Certificates represents a
$100,000 Denomination. A Single Certificate for the Residual Certificate
represents a $100 Denomination. A Single Certificate for the Class B-4, Class
B-5 and Class B-6 Certificates represents a $250,000 Denomination.

      Section 11.23 Servicing Fee Rate.

      The rate used to calculate the Servicing Fee is equal to such rate as
is set forth on the Mortgage Loan Schedule with respect to a Mortgage Loan.

      Section 11.24 Master Servicing Fee Rate.

      The rate used to calculate the Master Servicing Fee for each Mortgage
Loan shall be 0.010% per annum.

      IN WITNESS WHEREOF, the Depositor, the Master Servicer and the Trustee
have caused their names to be signed hereto by their respective officers
thereunto duly authorized, all as of the day and year first above written.

                                       WELLS FARGO ASSET SECURITIES
                                          CORPORATION
                                           as Depositor

                                       By: /s/ Bradley A. Davis
                                           --------------------------------
                                           Name: Bradley A. Davis
                                           Title: Vice President

                                       WELLS FARGO BANK, N.A.
                                           as Master Servicer

                                       By: /s/ Christopher Furlow
                                           --------------------------------
                                           Name: Christopher Furlow
                                           Title: Assistant Vice President

                                       HSBC BANK USA, NATIONAL ASSOCIATION
                                          as Trustee

                                       By: /s/ Alexander Pabon
                                           --------------------------------
                                           Name: Alexander Pabon
                                           Title: Vice President

<PAGE>

STATE OF MARYLAND       )
                        ss.:
COUNTY OF FREDERICK     )

            On this 20th day of December, 2007, before me, a notary public in
and for the State of Maryland, personally appeared Bradley A. Davis, known to
me who, being by me duly sworn, did depose and say that he resides at
Cooksville, Maryland; that he is a Vice President of Wells Fargo Asset
Securities Corporation, a Delaware corporation, one of the parties that
executed the foregoing instrument; and that he signed his name thereto by
order of the Board of Directors of said corporation.

_________________________
Notary Public

[NOTARIAL SEAL]

<PAGE>

STATE OF MARYLAND       )
                        ss.:
COUNTY OF HOWARD        )

            On this 20th day of December, 2007, before me, the undersigned
officer, personally appeared Christopher Furlow, and acknowledged to me to be
an Assistant Vice President of Wells Fargo Bank, National Association, and
that as such officer, being duly authorized to do so pursuant to such
entity's by-laws or a resolution of its board of directors, executed and
acknowledged the foregoing instrument for the purposes therein contained, by
signing the name of such entity by himself/herself as such officer as his/her
free and voluntary act and deed and the free and voluntary act and deed of
said entity.

            IN WITNESS WHEREOF, I hereunto set my hand and official seal.

_________________________
Notary Public

[NOTARIAL SEAL]

<PAGE>

STATE OF NEW YORK       )
                        ss.:
COUNTY OF NEW YORK      )

            On this 20th day of December, 2007, before me, a notary public in
and for the State of New York, personally appeared Alexander Pabon, known to me
who, being by me duly sworn, did depose and say that he is a Vice President of
HSBC Bank USA, National Association, a national banking association, one of the
parties that executed the foregoing instrument; and that he signed his name
thereto by order of the Board of Directors of said association.

_________________________
Notary Public

[NOTARIAL SEAL]

<PAGE>

                                   SCHEDULE I

                    Wells Fargo Asset Securities Corporation,
               Mortgage Pass-Through Certificates, Series 2007-17
                 Applicable Unscheduled Principal Receipt Period

                                    Full Unscheduled        Partial Unscheduled
Servicer                           Principal Receipts       Principal Receipts
-----------------------------      ------------------       -------------------
Wells Fargo Bank (Type 1
Mortgage Loans)                        Mid-Month                 Mid-Month
Colonial Savings, F.A.                 Mid-Month                Prior Month
--------------------------------------------------------------------------------

<PAGE>

                                   EXHIBIT A-1
                     [FORM OF FACE OF CLASS A-1 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
 REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE
 & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                            SERIES 2007-17, CLASS A-1

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                               first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE IS AN EXCHANGEABLE CERTIFICATE AS DESCRIBED IN THE
AGREEMENT REFERENCED HEREIN.

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE BALANCE OF THIS CERTIFICATE WILL
BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY, THE OUTSTANDING
BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS THAN THE MAXIMUM INITIAL
PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date: December 1, 2007

CUSIP No.: 94986Q AA1                  First Distribution Date: January 25, 2008

ISIN No.: US94986QAA13                 Denomination: $

Percentage Interest evidenced          Maximum Initial Principal
by this Certificate: %                 Balance: $

Final Scheduled Maturity Date:
January 25, 2038

<PAGE>

            THIS CERTIFIES THAT ___________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class A-1 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, first
lien, one- to four-family residential mortgage loans (the "Mortgage Loans"),
other than the Fixed Retained Yield, if any, with respect thereto, formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of December 20, 2007 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and HSBC Bank USA, National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

            Pursuant to the terms of the Agreement, a distribution will be made
on the 25th day of each month or, if such 25th day is not a Business Day, the
Business Day immediately following (the "Distribution Date"), commencing on the
first Distribution Date specified above, to the Person in whose name this
Certificate is registered at the close of business on the Record Date, in an
amount equal to the product of the Percentage Interest evidenced by this
Certificate and the amount required to be distributed to Holders of the Class
A-1 Certificates on such Distribution Date, subject to adjustment in certain
events as specified in the Agreement. The Class A-1 Certificates will be
entitled to distributions of principal and interest in accordance with the
provisions of the Agreement.

            Distributions on this Certificate will be made by the Paying Agent
by check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person has
notified the Paying Agent pursuant to the Agreement that such payments are to be
made by wire transfer of immediately available funds. Notwithstanding the above,
the final distribution on this Certificate will be made after due notice of the
pendency of such distribution and only upon presentation and surrender of this
Certificate at the office or agency of the Paying Agent specified for that
purpose in the notice of final distribution.

            Reference is hereby made to the further provisions of this
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

            This Certificate represents beneficial ownership of an interest in
each Related Exchangeable REMIC Certificate.

            Unless this Certificate has been countersigned by an authorized
officer of the Authenticating Agent, by manual signature, this Certificate shall
not be entitled to any benefit under the Agreement or be valid for any purpose.

<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
     Authenticating Agent

By ________________________
      Authorized Officer

<PAGE>

                                   EXHIBIT A-2

                     [FORM OF FACE OF CLASS A-2 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
 REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE
 & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                            SERIES 2007-17, CLASS A-2

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                               first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE IS AN EXCHANGEABLE REMIC CERTIFICATE AS DESCRIBED
IN THE AGREEMENT REFERENCED HEREIN.

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE MAXIMUM INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date: December 1, 2007

CUSIP No.: 94986Q AB9                  First Distribution Date: January 25, 2008

ISIN No.: US94986QAB95                 Denomination: $

Percentage Interest evidenced          Maximum Initial Principal
by this Certificate: %                 Balance: $

Final Scheduled Maturity Date:
January 25, 2038

<PAGE>

            THIS CERTIFIES THAT ___________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class A-2 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, first
lien, one- to four-family residential mortgage loans (the "Mortgage Loans"),
other than the Fixed Retained Yield, if any, with respect thereto, formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of December 20, 2007 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and HSBC Bank USA, National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

            Pursuant to the terms of the Agreement, a distribution will be made
on the 25th day of each month or, if such 25th day is not a Business Day, the
Business Day immediately following (the "Distribution Date"), commencing on the
first Distribution Date specified above, to the Person in whose name this
Certificate is registered at the close of business on the Record Date, in an
amount equal to the product of the Percentage Interest evidenced by this
Certificate and the Class A Distribution Amount for the Class A-2 Certificates
required to be distributed to Holders of the Class A-2 Certificates on such
Distribution Date, subject to adjustment in certain events as specified in the
Agreement. Distributions in reduction of the Principal Balance of certain
Classes of Class A Certificates may not commence on the first Distribution Date
specified above. Distributions of principal will be allocated among the Classes
of Class A Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class A-2 Certificates applicable to each Distribution
Date will be 6.000% per annum. The amount of interest which accrues on this
Certificate in any month will be subject to reduction with respect to any
Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class A-2 Certificates, as
described in the Agreement.

            Distributions on this Certificate will be made by the Paying Agent
by check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person has
notified the Paying Agent pursuant to the Agreement that such payments are to be
made by wire transfer of immediately available funds. Notwithstanding the above,
the final distribution in reduction of the Principal Balance of this Certificate
will be made after due notice of the pendency of such distribution and only upon
presentation and surrender of this Certificate at the office or agency of the
Paying Agent specified for that purpose in the notice of final distribution.

            Reference is hereby made to the further provisions of this
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

            This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

            Unless this Certificate has been countersigned by an authorized
officer of the Authenticating Agent, by manual signature, this Certificate shall
not be entitled to any benefit under the Agreement or be valid for any purpose.

<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
     Authenticating Agent

By ________________________
      Authorized Officer

<PAGE>

                                   EXHIBIT A-3

                     [FORM OF FACE OF CLASS A-3 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
 REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE
 & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                            SERIES 2007-17, CLASS A-3

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                               first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE IS AN EXCHANGEABLE REMIC CERTIFICATE AS DESCRIBED
IN THE AGREEMENT REFERENCED HEREIN.

            AFTER THE SUBORDINATION DEPLETION DATE, THE PRINCIPAL PORTION OF
REALIZED LOSSES ALLOCATED TO THE CLASS A-2 CERTIFICATES WILL BE BORNE BY THE
CLASS A-3 CERTIFICATES AS DESCRIBED IN THE AGREEMENT.

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE MAXIMUM INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date: December 1, 2007

CUSIP No.: 94986Q AC7                  First Distribution Date: January 25, 2008

ISIN No.: US94986QAC78                 Denomination: $

Percentage Interest evidenced          Maximum Initial Principal
by this Certificate: %                 Balance: $

Final Scheduled Maturity Date:
January 25, 2038

<PAGE>

            THIS CERTIFIES THAT ___________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class A-3 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, first
lien, one- to four-family residential mortgage loans (the "Mortgage Loans"),
other than the Fixed Retained Yield, if any, with respect thereto, formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of December 20, 2007 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and HSBC Bank USA, National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

            Pursuant to the terms of the Agreement, a distribution will be made
on the 25th day of each month or, if such 25th day is not a Business Day, the
Business Day immediately following (the "Distribution Date"), commencing on the
first Distribution Date specified above, to the Person in whose name this
Certificate is registered at the close of business on the Record Date, in an
amount equal to the product of the Percentage Interest evidenced by this
Certificate and the Class A Distribution Amount for the Class A-3 Certificates
required to be distributed to Holders of the Class A-3 Certificates on such
Distribution Date, subject to adjustment in certain events as specified in the
Agreement. Distributions in reduction of the Principal Balance of certain
Classes of Class A Certificates may not commence on the first Distribution Date
specified above. Distributions of principal will be allocated among the Classes
of Class A Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class A-3 Certificates applicable to each Distribution
Date will be 6.000% per annum. The amount of interest which accrues on this
Certificate in any month will be subject to reduction with respect to any
Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class A-3 Certificates, as
described in the Agreement.

            Distributions on this Certificate will be made by the Paying Agent
by check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person has
notified the Paying Agent pursuant to the Agreement that such payments are to be
made by wire transfer of immediately available funds. Notwithstanding the above,
the final distribution in reduction of the Principal Balance of this Certificate
will be made after due notice of the pendency of such distribution and only upon
presentation and surrender of this Certificate at the office or agency of the
Paying Agent specified for that purpose in the notice of final distribution.

            Reference is hereby made to the further provisions of this
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

            This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

            Unless this Certificate has been countersigned by an authorized
officer of the Authenticating Agent, by manual signature, this Certificate shall
not be entitled to any benefit under the Agreement or be valid for any purpose.

<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
     Authenticating Agent

By ________________________
      Authorized Officer

<PAGE>

                                  EXHIBIT A-PO
                    [FORM OF FACE OF CLASS A-PO CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
 REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE
 & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2007-17, CLASS A-PO

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                               first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                       Cut-Off Date: December 1, 2007

CUSIP No.: 94986Q AD5                 First Distribution Date: January 25, 2008

ISIN No.: US94986QAD51                Denomination: $

Percentage Interest evidenced         Final Scheduled Maturity Date: January 25,
by this Certificate: %                2038

<PAGE>

            THIS CERTIFIES THAT ___________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class A-PO Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, first
lien, one- to four-family residential mortgage loans (the "Mortgage Loans"),
other than the Fixed Retained Yield, if any, with respect thereto, formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of December 20, 2007 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and HSBC Bank USA, National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

            Pursuant to the terms of the Agreement, a distribution will be made
on the 25th day of each month or, if such 25th day is not a Business Day, the
Business Day immediately following (the "Distribution Date"), commencing on the
first Distribution Date specified above, to the Person in whose name this
Certificate is registered at the close of business on the Record Date, in an
amount equal to the product of the Percentage Interest evidenced by this
Certificate and the Class A Distribution Amount for the Class A-PO Certificates
required to be distributed to Holders of the Class A-PO Certificates on such
Distribution Date, subject to adjustment in certain events as specified in the
Agreement. The Class A-PO Certificates are principal only Certificates and will
not be entitled to distributions in respect of interest.

            Distributions on this Certificate will be made by the Paying Agent
by check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person has
notified the Paying Agent pursuant to the Agreement that such payments are to be
made by wire transfer of immediately available funds. Notwithstanding the above,
the final distribution in reduction of the Principal Balance of this Certificate
will be made after due notice of the pendency of such distribution and only upon
presentation and surrender of this Certificate at the office or agency of the
Paying Agent specified for that purpose in the notice of final distribution.

            Reference is hereby made to the further provisions of this
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

            This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

            Unless this Certificate has been countersigned by an authorized
officer of the Authenticating Agent, by manual signature, this Certificate shall
not be entitled to any benefit under the Agreement or be valid for any purpose.

<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer

<PAGE>

                                   EXHIBIT A-R
                     [FORM OF FACE OF CLASS A-R CERTIFICATE]

FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE REPRESENTS THE "RESIDUAL
INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT" AS THOSE TERMS ARE
DEFINED, RESPECTIVELY, IN SECTIONS 860G(a)(2) AND 860D OF THE INTERNAL REVENUE
CODE OF 1986, AS AMENDED (THE "CODE"). A TRANSFEREE OF THIS CERTIFICATE, BY
ACCEPTANCE HEREOF, IS DEEMED TO HAVE ACCEPTED THIS CERTIFICATE SUBJECT TO
CERTAIN RESTRICTIONS ON TRANSFERABILITY, AS SET FORTH IN SECTION 5.02(d) OF THE
AGREEMENT, AND SHALL BE REQUIRED TO FURNISH AN AFFIDAVIT TO THE TRANSFEROR AND
THE MASTER SERVICER TO THE EFFECT THAT, AMONG OTHER THINGS, IT IS NOT A
DISQUALIFIED ORGANIZATION, AS SUCH TERM IS DEFINED IN CODE SECTION 860E(e)(5),
AN AGENT (INCLUDING A BROKER, NOMINEE OR OTHER MIDDLEMAN) FOR A DISQUALIFIED
ORGANIZATION OR A NON-PERMITTED FOREIGN HOLDER, AS DEFINED IN SECTION 5.02(d) OF
THE AGREEMENT AND TO HAVE AGREED TO SUCH AMENDMENTS TO THE AGREEMENT AS MAY BE
REQUIRED TO FURTHER EFFECTUATE THE RESTRICTIONS ON TRANSFERS TO DISQUALIFIED
ORGANIZATIONS, AGENTS THEREOF OR NON-PERMITTED FOREIGN HOLDERS.

THE HOLDER OF THIS CLASS A-R CERTIFICATE, BY ACCEPTANCE HEREOF, IS DEEMED TO
HAVE AGREED TO THE DESIGNATION OF THE MASTER SERVICER AS ITS AGENT TO ACT AS
"TAX MATTERS PERSON" OF THE REMIC TO PERFORM THE FUNCTIONS OF A "TAX MATTERS
PARTNER" FOR PURPOSES OF SUBCHAPTER C OF CHAPTER 63 OF SUBTITLE F OF THE CODE,
OR, IF SO REQUESTED BY THE MASTER SERVICER, TO ACT AS TAX MATTERS PERSON OF THE
REMIC.

THIS CERTIFICATE MAY NOT BE PURCHASED BY OR TRANSFERRED TO ANY PERSON WHICH IS
AN EMPLOYEE BENEFIT PLAN OR OTHER RETIREMENT ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE CODE OR A GOVERNMENTAL PLAN, AS DEFINED IN SECTION 3(32) OF
ERISA SUBJECT TO ANY FEDERAL, STATE OR LOCAL LAW WHICH IS, TO A MATERIAL EXTENT,
SIMILAR TO THE FOREGOING PROVISIONS OF ERISA OR THE CODE (COLLECTIVELY, A
"PLAN"), OR ANY PERSON ACTING ON BEHALF OF OR INVESTING THE ASSETS OF A PLAN.

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE
                            SERIES 2007-17, CLASS A-R

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                               first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                  Cut-Off Date: December 1, 2007

CUSIP No.: 94986Q AE3            First Distribution Date: January 25, 2008

ISIN No.: US94986QAE35           Denomination: $

Percentage Interest evidenced
by this Certificate: %           Final Scheduled Maturity Date: January 25, 2038

<PAGE>

            THIS CERTIFIES THAT __________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holder of the Class A-R Certificate with respect to a Trust
Estate consisting of a pool of fixed interest rate, monthly pay, first lien,
one- to four-family residential mortgage loans (the "Mortgage Loans"), other
than the Fixed Retained Yield, if any, with respect thereto, formed by Wells
Fargo Asset Securities Corporation (hereinafter called the "Depositor," which
term includes any successor entity under the Agreement referred to below). The
Trust Estate was created pursuant to a Pooling and Servicing Agreement dated as
of December 20, 2007 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and HSBC Bank USA, National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

            Pursuant to the terms of the Agreement, a distribution will be made
on the 25th day of each month or, if such 25th day is not a Business Day, the
Business Day immediately following (the "Distribution Date"), commencing on the
first Distribution Date specified above, to the Person in whose name this
Certificate is registered at the close of business on the Record Date, in an
amount equal to the product of the Percentage Interest evidenced by this
Certificate and the Class A Distribution Amount for the Class A-R Certificate
required to be distributed to the Holder of the Class A-R Certificate on such
Distribution Date, subject to adjustment in certain events as specified in the
Agreement. Distributions in reduction of the Principal Balance of certain
Classes of Class A Certificates may not commence on the first Distribution Date
specified above. Distributions of principal will be allocated among the Classes
of Class A Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class A-R Certificate applicable to each Distribution
Date will be 6.000% per annum. The amount of interest which accrues on this
Certificate in any month will be subject to reduction with respect to any
Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class A-R Certificate, as
described in the Agreement.

            Distributions on this Certificate will be made by the Paying Agent
by check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person has
notified the Paying Agent pursuant to the Agreement that such payments are to be
made by wire transfer of immediately available funds. Notwithstanding the above,
the final distribution on this Certificate will be made after due notice of the
pendency of such distribution and only upon presentation and surrender of this
Certificate at the office or agency of the Paying Agent specified for that
purpose in the notice of final distribution.

            Reference is hereby made to the further provisions of this
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

            Unless this Certificate has been countersigned by an authorized
officer of the Authenticating Agent, by manual signature, this Certificate shall
not be entitled to any benefit under the Agreement or be valid for any purpose.

<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
      Authorized Officer

<PAGE>

                                   EXHIBIT B-1
                     [FORM OF FACE OF CLASS B-1 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE CLASS A CERTIFICATES
AS DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                            SERIES 2007-17, CLASS B-1

   evidencing an interest in a pool of fixed interest rate, monthly pay, first
          lien, one- to four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                       Cut-Off Date: December 1, 2007

CUSIP No.: 94986Q AF0                 First Distribution Date: January 25, 2008

ISIN No.: US94986QAF00                Denomination: $

Percentage Interest evidenced         Final Scheduled Maturity Date: January 25,
by this Certificate: %                2038

<PAGE>

            THIS CERTIFIES THAT ____________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class B-1 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, first
lien, one- to four-family residential mortgage loans (the "Mortgage Loans"),
other than the Fixed Retained Yield, if any, with respect thereto, formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of December 20, 2007 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and HSBC Bank USA, National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

            Pursuant to the terms of the Agreement, a distribution will be made
on the 25th day of each month or, if such 25th day is not a Business Day, the
Business Day immediately following (the "Distribution Date"), commencing on the
first Distribution Date specified above, to the Person in whose name this
Certificate is registered at the close of business on the Record Date, in an
amount equal to the product of the Percentage Interest evidenced by this
Certificate and, subject to the prior rights of the Class A Certificates as
specified in the Agreement, any Class B-1 Distribution Amount required to be
distributed to Holders of the Class B-1 Certificates on such Distribution Date,
subject to adjustment, in certain events, as specified in the Agreement. The
pass-through rate on the Class B-1 Certificates applicable to each Distribution
Date will be 6.000% per annum. The amount of interest which accrues on this
Certificate in any month will be subject to reduction with respect to any
Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to the
Class B-1 Certificates, as described in the Agreement.

            Distributions on this Certificate will be made by the Paying Agent
by check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person has
notified the Paying Agent pursuant to the Agreement that such payments are to be
made by wire transfer of immediately available funds. Notwithstanding the above,
the final distribution in reduction of the Principal Balance of this Certificate
will be made after due notice of the pendency of such distribution and only upon
presentation and surrender of this Certificate at the office or agency of the
Paying Agent specified for that purpose in the notice of final distribution.

            Reference is hereby made to the further provisions of this
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

            This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

            Unless this Certificate has been countersigned by an authorized
officer of the Authenticating Agent, by manual signature, this Certificate shall
not be entitled to any benefit under the Agreement or be valid for any purpose.

<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer

<PAGE>

                                   EXHIBIT B-2
                     [FORM OF FACE OF CLASS B-2 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE CLASS A CERTIFICATES
AND THE CLASS B-1 CERTIFICATES AS DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                            SERIES 2007-17, CLASS B-2

   evidencing an interest in a pool of fixed interest rate, monthly pay, first
          lien, one- to four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                       Cut-Off Date: December 1, 2007

CUSIP No.: 94986Q AG8                 First Distribution Date: January 25, 2008

ISIN No.: US94986QAG82                Denomination: $

Percentage Interest evidenced         Final Scheduled Maturity Date: January 25,
by this Certificate: %                2038

<PAGE>

            THIS CERTIFIES THAT ____________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class B-2 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, first
lien, one- to four-family residential mortgage loans (the "Mortgage Loans"),
other than the Fixed Retained Yield, if any, with respect thereto, formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of December 20, 2007 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and HSBC Bank USA, National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

            Pursuant to the terms of the Agreement, a distribution will be made
on the 25th day of each month or, if such 25th day is not a Business Day, the
Business Day immediately following (the "Distribution Date"), commencing on the
first Distribution Date specified above, to the Person in whose name this
Certificate is registered at the close of business on the Record Date, in an
amount equal to the product of the Percentage Interest evidenced by this
Certificate and, subject to the prior rights of the Class A Certificates and
each Class of Class B Certificates bearing a lower numerical designation as
specified in the Agreement, any Class B-2 Distribution Amount required to be
distributed to Holders of the Class B-2 Certificates on such Distribution Date,
subject to adjustment, in certain events, as specified in the Agreement. The
pass-through rate on the Class B-2 Certificates applicable to each Distribution
Date will be 6.000% per annum. The amount of interest which accrues on this
Certificate in any month will be subject to reduction with respect to any
Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to the
Class B-2 Certificates, as described in the Agreement.

            Distributions on this Certificate will be made by the Paying Agent
by check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person has
notified the Paying Agent pursuant to the Agreement that such payments are to be
made by wire transfer of immediately available funds. Notwithstanding the above,
the final distribution in reduction of the Principal Balance of this Certificate
will be made after due notice of the pendency of such distribution and only upon
presentation and surrender of this Certificate at the office or agency of the
Paying Agent specified for that purpose in the notice of final distribution.

            Reference is hereby made to the further provisions of this
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

            This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

            Unless this Certificate has been countersigned by an authorized
officer of the Authenticating Agent, by manual signature, this Certificate shall
not be entitled to any benefit under the Agreement or be valid for any purpose.

<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer

<PAGE>

                                   EXHIBIT B-3

                     [FORM OF FACE OF CLASS B-3 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE CLASS A
CERTIFICATES, THE CLASS B-1 CERTIFICATES AND THE CLASS B-2 CERTIFICATES AS
DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                            SERIES 2007-17, CLASS B-3

   evidencing an interest in a pool of fixed interest rate, monthly pay, first
          lien, one- to four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                       Cut-Off Date: December 1, 2007

CUSIP No.: 94986Q AH6                 First Distribution Date: January 25, 2008

ISIN No.: US94986QAH65                Denomination: $

Percentage Interest evidenced         Final Scheduled Maturity Date: January 25,
by this Certificate: %                2038

<PAGE>

            THIS CERTIFIES THAT _______________________________ is the
registered owner of the Percentage Interest evidenced by this Certificate in
monthly distributions to the Holders of the Class B-3 Certificates with respect
to a Trust Estate consisting of a pool of fixed interest rate, monthly pay,
first lien, one- to four-family residential mortgage loans (the "Mortgage
Loans"), other than the Fixed Retained Yield, if any, with respect thereto,
formed by Wells Fargo Asset Securities Corporation (hereinafter called the
"Depositor," which term includes any successor entity under the Agreement
referred to below). The Trust Estate was created pursuant to a Pooling and
Servicing Agreement dated as of December 20, 2007 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and HSBC Bank USA, National Association, as trustee (the "Trustee"), a summary
of certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

            Pursuant to the terms of the Agreement, a distribution will be made
on the 25th day of each month or, if such 25th day is not a Business Day, the
Business Day immediately following (the "Distribution Date"), commencing on the
first Distribution Date specified above, to the Person in whose name this
Certificate is registered at the close of business on the Record Date, in an
amount equal to the product of the Percentage Interest evidenced by this
Certificate and, subject to the prior rights of the Class A Certificates and
each Class of Class B Certificates bearing a lower numerical designation as
specified in the Agreement, any Class B-3 Distribution Amount required to be
distributed to Holders of the Class B-3 Certificates on such Distribution Date,
subject to adjustment, in certain events, as specified in the Agreement. The
pass-through rate on the Class B-3 Certificates applicable to each Distribution
Date will be 6.000% per annum. The amount of interest which accrues on this
Certificate in any month will be subject to reduction with respect to any
Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to the
Class B-3 Certificates, as described in the Agreement.

            Distributions on this Certificate will be made by the Paying Agent
by check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person has
notified the Paying Agent pursuant to the Agreement that such payments are to be
made by wire transfer of immediately available funds. Notwithstanding the above,
the final distribution in reduction of the Principal Balance of this Certificate
will be made after due notice of the pendency of such distribution and only upon
presentation and surrender of this Certificate at the office or agency of the
Paying Agent specified for that purpose in the notice of final distribution.

            Reference is hereby made to the further provisions of this
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

            This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

            Unless this Certificate has been countersigned by an authorized
officer of the Authenticating Agent, by manual signature, this Certificate shall
not be entitled to any benefit under the Agreement or be valid for any purpose.

<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer

<PAGE>

                                   EXHIBIT B-4

                     [FORM OF FACE OF CLASS B-4 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE CLASS A
CERTIFICATES, THE CLASS B-1 CERTIFICATES, THE CLASS B-2 CERTIFICATES AND THE
CLASS B-3 CERTIFICATES AS DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

THIS CERTIFICATE HAS NOT BEEN AND WILL NOT BE REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE
RESOLD OR TRANSFERRED UNLESS IT IS REGISTERED PURSUANT TO SUCH ACT AND LAWS OR
IS SOLD OR TRANSFERRED IN TRANSACTIONS WHICH ARE EXEMPT FROM REGISTRATION UNDER
SUCH ACT AND UNDER APPLICABLE STATE LAW AND IS TRANSFERRED IN ACCORDANCE WITH
THE PROVISIONS OF SECTION 5.02 OF THE AGREEMENT REFERRED TO HEREIN.

THE INITIAL PURCHASER IN THIS CERTIFICATE, AND EACH SUBSEQUENT PURCHASER OF THIS
CERTIFICATE, BY PURCHASING THIS CERTIFICATE OR AN INTEREST HEREIN, IS DEEMED TO
HAVE AGREED TO COMPLY WITH CERTAIN TRANSFER REQUIREMENTS SET FORTH IN THE
POOLING AND SERVICING AGREEMENT REFERRED TO HEREIN.

EXCEPT AS PROVIDED IN SECTION 5.02(C) OF THE AGREEMENT REFERRED TO HEREIN, THIS
CERTIFICATE MAY NOT BE PURCHASED BY OR TRANSFERRED TO ANY PERSON THAT HAS NOT
DELIVERED A REPRESENTATION LETTER STATING EITHER (A) THAT THE TRANSFEREE IS NOT
AN EMPLOYEE BENEFIT PLAN OR OTHER RETIREMENT ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE"), OR A
GOVERNMENTAL PLAN, AS DEFINED IN SECTION 3(32) OF ERISA, SUBJECT TO ANY FEDERAL,
STATE OR LOCAL LAW WHICH IS, TO A MATERIAL EXTENT, SIMILAR TO THE FOREGOING
PROVISIONS OF ERISA OR THE CODE (COLLECTIVELY, A "PLAN"), AND IS NOT ACTING ON
BEHALF OF OR INVESTING THE ASSETS OF A PLAN OR (B) SUBJECT TO CERTAIN CONDITIONS
SET FORTH IN THE AGREEMENT, THAT THE SOURCE OF FUNDS USED TO PURCHASE THIS
CERTIFICATE IS AN "INSURANCE COMPANY GENERAL ACCOUNT." EACH PERSON WHO ACQUIRES
THIS CERTIFICATE OR ANY INTEREST THEREIN SHALL BE DEEMED TO HAVE MADE THE
REPRESENTATIONS REQUIRED BY THE REPRESENTATION LETTER REFERRED TO IN THE
PRECEDING SENTENCE, UNLESS SUCH PERSON SHALL HAVE PROVIDED SUCH REPRESENTATION
LETTER OR THE OPINION OF COUNSEL REFERRED TO IN SECTION 5.02(C) OF THE AGREEMENT
REFERRED TO HEREIN TO THE MASTER SERVICER AND DEPOSITOR.

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE
                            SERIES 2007-17, CLASS B-4

   evidencing an interest in a pool of fixed interest rate, monthly pay, first
          lien, one- to four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                       Cut-Off Date: December 1, 2007

CUSIP No.: 94986Q AJ2                 First Distribution Date: January 25, 2008

ISIN No.: US94986QAJ22                Denomination: $

Percentage Interest evidenced         Final Scheduled Maturity Date: January 25,
by this Certificate: %                2038

<PAGE>

            THIS CERTIFIES THAT ____________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class B-4 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, first
lien, one- to four-family residential mortgage loans (the "Mortgage Loans"),
other than the Fixed Retained Yield, if any, with respect thereto, formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of December 20, 2007 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and HSBC Bank USA, National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

            Pursuant to the terms of the Agreement, a distribution will be made
on the 25th day of each month or, if such 25th day is not a Business Day, the
Business Day immediately following (the "Distribution Date"), commencing on the
first Distribution Date specified above, to the Person in whose name this
Certificate is registered at the close of business on the Record Date, in an
amount equal to the product of the Percentage Interest evidenced by this
Certificate and, subject to the prior rights of the Class A Certificates and
each Class of Class B Certificates bearing a lower numerical designation as
specified in the Agreement, any Class B-4 Distribution Amount required to be
distributed to Holders of the Class B-4 Certificates on such Distribution Date,
subject to adjustment, in certain events, as specified in the Agreement. The
pass-through rate on the Class B-4 Certificates applicable to each Distribution
Date will be 6.000% per annum. The amount of interest which accrues on this
Certificate in any month will be subject to reduction with respect to any
Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to the
Class B-4 Certificates, as described in the Agreement.

            Distributions on this Certificate will be made by the Paying Agent
by check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person has
notified the Paying Agent pursuant to the Agreement that such payments are to be
made by wire transfer of immediately available funds. Notwithstanding the above,
the final distribution in reduction of the Principal Balance of this Certificate
will be made after due notice of the pendency of such distribution and only upon
presentation and surrender of this Certificate at the office or agency of the
Paying Agent specified for that purpose in the notice of final distribution.

            No transfer of a Class B-4 Certificate will be made unless such
transfer is exempt from the registration requirements of the Securities Act of
1933, as amended, and any applicable state securities laws or is made in
accordance with said Act and laws. In the event that such a transfer is desired
to be made by the Holder hereof, the transferee will be required to execute an
investment letter in the form described in the Agreement. The Holder hereof
desiring to effect such transfer shall, and does hereby agree to, indemnify the
Trustee, the Depositor, the Master Servicer, and any Paying Agent against any
liability that may result if the transfer is not so exempt or is not made in
accordance with such Federal and state laws. The representations required in any
investment letter shall be deemed to have been made in connection with a
transfer of a Class B-4 Certificate that is a Book-Entry Certificate. In
connection with any such transfer, the Master Servicer will also require (i) a
representation letter, in the form as described in the Agreement, stating either
(a) that the transferee is not a Plan and is not acting on behalf of a Plan or
using the assets of a Plan to effect such purchase or (b) subject to certain
conditions described in the Agreement, that the source of funds used to purchase
this Certificate is an "insurance company general account," or (ii) if such
transferee is a Plan, (a) an opinion of counsel acceptable to and in form and
substance satisfactory to the Master Servicer and the Depositor with respect to
certain matters and (b) such other documentation as the Depositor or the Master
Servicer may require, as described in the Agreement. For purposes of clause (i)
of this paragraph, each person who acquires this certificate or any interest
therein shall be deemed to have made the representations required by the
representation letter referred to in the preceding sentence, unless such person
shall have provided such representation letter or the opinion of counsel
referred to in the preceding sentence to the Depositor and Master Servicer.

            Reference is hereby made to the further provisions of this
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

            This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

            Unless this Certificate has been countersigned by an authorized
officer of the Authenticating Agent, by manual signature, this Certificate shall
not be entitled to any benefit under the Agreement or be valid for any purpose.

<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer

<PAGE>

                                   EXHIBIT B-5
                     [FORM OF FACE OF CLASS B-5 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE CLASS A
CERTIFICATES, THE CLASS B-1 CERTIFICATES, THE CLASS B-2 CERTIFICATES, THE CLASS
B-3 CERTIFICATES AND THE CLASS B-4 CERTIFICATES AS DESCRIBED IN THE AGREEMENT
REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

THIS CERTIFICATE HAS NOT BEEN AND WILL NOT BE REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE
RESOLD OR TRANSFERRED UNLESS IT IS REGISTERED PURSUANT TO SUCH ACT AND LAWS OR
IS SOLD OR TRANSFERRED IN TRANSACTIONS WHICH ARE EXEMPT FROM REGISTRATION UNDER
SUCH ACT AND UNDER APPLICABLE STATE LAW AND IS TRANSFERRED IN ACCORDANCE WITH
THE PROVISIONS OF SECTION 5.02 OF THE AGREEMENT REFERRED TO HEREIN.

THE INITIAL PURCHASER IN THIS CERTIFICATE, AND EACH SUBSEQUENT PURCHASER OF THIS
CERTIFICATE, BY PURCHASING THIS CERTIFICATE OR AN INTEREST HEREIN, IS DEEMED TO
HAVE AGREED TO COMPLY WITH CERTAIN TRANSFER REQUIREMENTS SET FORTH IN THE
POOLING AND SERVICING AGREEMENT REFERRED TO HEREIN.

EXCEPT AS PROVIDED IN SECTION 5.02(C) OF THE AGREEMENT REFERRED TO HEREIN, THIS
CERTIFICATE MAY NOT BE PURCHASED BY OR TRANSFERRED TO ANY PERSON THAT HAS NOT
DELIVERED A REPRESENTATION LETTER STATING EITHER (A) THAT THE TRANSFEREE IS NOT
AN EMPLOYEE BENEFIT PLAN OR OTHER RETIREMENT ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE"), OR A
GOVERNMENTAL PLAN, AS DEFINED IN SECTION 3(32) OF ERISA, SUBJECT TO ANY FEDERAL,
STATE OR LOCAL LAW WHICH IS, TO A MATERIAL EXTENT, SIMILAR TO THE FOREGOING
PROVISIONS OF ERISA OR THE CODE (COLLECTIVELY, A "PLAN"), AND IS NOT ACTING ON
BEHALF OF OR INVESTING THE ASSETS OF A PLAN OR (B) SUBJECT TO CERTAIN CONDITIONS
SET FORTH IN THE AGREEMENT, THAT THE SOURCE OF FUNDS USED TO PURCHASE THIS
CERTIFICATE IS AN "INSURANCE COMPANY GENERAL ACCOUNT." EACH PERSON WHO ACQUIRES
THIS CERTIFICATE OR ANY INTEREST THEREIN SHALL BE DEEMED TO HAVE MADE THE
REPRESENTATIONS REQUIRED BY THE REPRESENTATION LETTER REFERRED TO IN THE
PRECEDING SENTENCE, UNLESS SUCH PERSON SHALL HAVE PROVIDED SUCH REPRESENTATION
LETTER OR THE OPINION OF COUNSEL REFERRED TO IN SECTION 5.02(C) OF THE AGREEMENT
REFERRED TO HEREIN TO THE MASTER SERVICER AND DEPOSITOR.

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE
                            SERIES 2007-17, CLASS B-5

   evidencing an interest in a pool of fixed interest rate, monthly pay, first
          lien, one- to four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                       Cut-Off Date: December 1, 2007

CUSIP No.: 94986Q AK9                 First Distribution Date: January 25, 2008

ISIN No.: US94986QAK94                Denomination: $

Percentage Interest evidenced         Final Scheduled Maturity Date: January 25,
by this Certificate: %                2038

<PAGE>

            THIS CERTIFIES THAT ____________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class B-5 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, first
lien, one- to four-family residential mortgage loans (the "Mortgage Loans"),
other than the Fixed Retained Yield, if any, with respect thereto, formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of December 20, 2007 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and HSBC Bank USA, National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

            Pursuant to the terms of the Agreement, a distribution will be made
on the 25th day of each month or, if such 25th day is not a Business Day, the
Business Day immediately following (the "Distribution Date"), commencing on the
first Distribution Date specified above, to the Person in whose name this
Certificate is registered at the close of business on the Record Date, in an
amount equal to the product of the Percentage Interest evidenced by this
Certificate and, subject to the prior rights of the Class A Certificates and
each Class of Class B Certificates bearing a lower numerical designation as
specified in the Agreement, any Class B-5 Distribution Amount required to be
distributed to Holders of the Class B-5 Certificates on such Distribution Date,
subject to adjustment, in certain events, as specified in the Agreement. The
pass-through rate on the Class B-5 Certificates applicable to each Distribution
Date will be 6.000% per annum. The amount of interest which accrues on this
Certificate in any month will be subject to reduction with respect to any
Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to the
Class B-5 Certificates, as described in the Agreement.

            Distributions on this Certificate will be made by the Paying Agent
by check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person has
notified the Paying Agent pursuant to the Agreement that such payments are to be
made by wire transfer of immediately available funds. Notwithstanding the above,
the final distribution in reduction of the Principal Balance of this Certificate
will be made after due notice of the pendency of such distribution and only upon
presentation and surrender of this Certificate at the office or agency of the
Paying Agent specified for that purpose in the notice of final distribution.

            No transfer of a Class B-5 Certificate will be made unless such
transfer is exempt from the registration requirements of the Securities Act of
1933, as amended, and any applicable state securities laws or is made in
accordance with said Act and laws. In the event that such a transfer is desired
to be made by the Holder hereof, the transferee will be required to execute an
investment letter in the form described in the Agreement. The Holder hereof
desiring to effect such transfer shall, and does hereby agree to, indemnify the
Trustee, the Depositor, the Master Servicer, and any Paying Agent against any
liability that may result if the transfer is not so exempt or is not made in
accordance with such Federal and state laws. The representations required in any
investment letter shall be deemed to have been made in connection with a
transfer of a Class B-5 Certificate that is a Book-Entry Certificate. In
connection with any such transfer, the Master Servicer will also require (i) a
representation letter, in the form as described in the Agreement, stating either
(a) that the transferee is not a Plan and is not acting on behalf of a Plan or
using the assets of a Plan to effect such purchase or (b) subject to certain
conditions described in the Agreement, that the source of funds used to purchase
this Certificate is an "insurance company general account," or (ii) if such
transferee is a Plan, (a) an opinion of counsel acceptable to and in form and
substance satisfactory to the Master Servicer and the Depositor with respect to
certain matters and (b) such other documentation as the Depositor or the Master
Servicer may require, as described in the Agreement. For purposes of clause (i)
of this paragraph, each person who acquires this certificate or any interest
therein shall be deemed to have made the representations required by the
representation letter referred to in the preceding sentence, unless such person
shall have provided such representation letter or the opinion of counsel
referred to in the preceding sentence to the Depositor and Master Servicer.

            Reference is hereby made to the further provisions of this
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

            This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

            Unless this Certificate has been countersigned by an authorized
officer of the Authenticating Agent, by manual signature, this Certificate shall
not be entitled to any benefit under the Agreement or be valid for any purpose.

<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer

<PAGE>

                                   EXHIBIT B-6
                     [FORM OF FACE OF CLASS B-6 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE CLASS A
CERTIFICATES, THE CLASS B-1 CERTIFICATES, THE CLASS B-2 CERTIFICATES, THE CLASS
B-3 CERTIFICATES, THE CLASS B-4 CERTIFICATES AND THE CLASS B-5 CERTIFICATES AS
DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

THIS CERTIFICATE HAS NOT BEEN AND WILL NOT BE REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE
RESOLD OR TRANSFERRED UNLESS IT IS REGISTERED PURSUANT TO SUCH ACT AND LAWS OR
IS SOLD OR TRANSFERRED IN TRANSACTIONS WHICH ARE EXEMPT FROM REGISTRATION UNDER
SUCH ACT AND UNDER APPLICABLE STATE LAW AND IS TRANSFERRED IN ACCORDANCE WITH
THE PROVISIONS OF SECTION 5.02 OF THE AGREEMENT REFERRED TO HEREIN.

THE INITIAL PURCHASER IN THIS CERTIFICATE, AND EACH SUBSEQUENT PURCHASER OF THIS
CERTIFICATE, BY PURCHASING THIS CERTIFICATE OR AN INTEREST HEREIN, IS DEEMED TO
HAVE AGREED TO COMPLY WITH CERTAIN TRANSFER REQUIREMENTS SET FORTH IN THE
POOLING AND SERVICING AGREEMENT REFERRED TO HEREIN.

EXCEPT AS PROVIDED IN SECTION 5.02(C) OF THE AGREEMENT REFERRED TO HEREIN, THIS
CERTIFICATE MAY NOT BE PURCHASED BY OR TRANSFERRED TO ANY PERSON THAT HAS NOT
DELIVERED A REPRESENTATION LETTER STATING EITHER (A) THAT THE TRANSFEREE IS NOT
AN EMPLOYEE BENEFIT PLAN OR OTHER RETIREMENT ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE"), OR A
GOVERNMENTAL PLAN, AS DEFINED IN SECTION 3(32) OF ERISA, SUBJECT TO ANY FEDERAL,
STATE OR LOCAL LAW WHICH IS, TO A MATERIAL EXTENT, SIMILAR TO THE FOREGOING
PROVISIONS OF ERISA OR THE CODE (COLLECTIVELY, A "PLAN"), AND IS NOT ACTING ON
BEHALF OF OR INVESTING THE ASSETS OF A PLAN OR (B) SUBJECT TO CERTAIN CONDITIONS
SET FORTH IN THE AGREEMENT, THAT THE SOURCE OF FUNDS USED TO PURCHASE THIS
CERTIFICATE IS AN "INSURANCE COMPANY GENERAL ACCOUNT." EACH PERSON WHO ACQUIRES
THIS CERTIFICATE OR ANY INTEREST THEREIN SHALL BE DEEMED TO HAVE MADE THE
REPRESENTATIONS REQUIRED BY THE REPRESENTATION LETTER REFERRED TO IN THE
PRECEDING SENTENCE, UNLESS SUCH PERSON SHALL HAVE PROVIDED SUCH REPRESENTATION
LETTER OR THE OPINION OF COUNSEL REFERRED TO IN SECTION 5.02(C) OF THE AGREEMENT
REFERRED TO HEREIN TO THE MASTER SERVICER AND DEPOSITOR.

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE
                            SERIES 2007-17, CLASS B-6

   evidencing an interest in a pool of fixed interest rate, monthly pay, first
          lien, one- to four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                       Cut-Off Date: December 1, 2007

CUSIP No.: 94986Q AL7                 First Distribution Date: January 25, 2008

ISIN No.: US94986QAL77                Denomination: $

Percentage Interest evidenced         Final Scheduled Maturity Date: January 25,
by this Certificate: %                2038

<PAGE>

            THIS CERTIFIES THAT ____________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class B-6 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, first
lien, one- to four-family residential mortgage loans (the "Mortgage Loans"),
other than the Fixed Retained Yield, if any, with respect thereto, formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of December 20, 2007 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and HSBC Bank USA, National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

            Pursuant to the terms of the Agreement, a distribution will be made
on the 25th day of each month or, if such 25th day is not a Business Day, the
Business Day immediately following (the "Distribution Date"), commencing on the
first Distribution Date specified above, to the Person in whose name this
Certificate is registered at the close of business on the Record Date, in an
amount equal to the product of the Percentage Interest evidenced by this
Certificate and, subject to the prior rights of the Class A Certificates and
each Class of Class B Certificates bearing a lower numerical designation as
specified in the Agreement, any Class B-6 Distribution Amount required to be
distributed to Holders of the Class B-6 Certificates on such Distribution Date,
subject to adjustment, in certain events, as specified in the Agreement. The
pass-through rate on the Class B-6 Certificates applicable to each Distribution
Date will be 6.000% per annum. The amount of interest which accrues on this
Certificate in any month will be subject to reduction with respect to any
Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to the
Class B-6 Certificates, as described in the Agreement.

            Distributions on this Certificate will be made by the Paying Agent
by check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person has
notified the Paying Agent pursuant to the Agreement that such payments are to be
made by wire transfer of immediately available funds. Notwithstanding the above,
the final distribution in reduction of the Principal Balance of this Certificate
will be made after due notice of the pendency of such distribution and only upon
presentation and surrender of this Certificate at the office or agency of the
Paying Agent specified for that purpose in the notice of final distribution.

            No transfer of a Class B-6 Certificate will be made unless such
transfer is exempt from the registration requirements of the Securities Act of
1933, as amended, and any applicable state securities laws or is made in
accordance with said Act and laws. In the event that such a transfer is desired
to be made by the Holder hereof, the transferee will be required to execute an
investment letter in the form described in the Agreement. The Holder hereof
desiring to effect such transfer shall, and does hereby agree to, indemnify the
Trustee, the Depositor, the Master Servicer, and any Paying Agent against any
liability that may result if the transfer is not so exempt or is not made in
accordance with such Federal and state laws. The representations required in any
investment letter shall be deemed to have been made in connection with a
transfer of a Class B-6 Certificate that is a Book-Entry Certificate. In
connection with any such transfer, the Master Servicer will also require (i) a
representation letter, in the form as described in the Agreement, stating either
(a) that the transferee is not a Plan and is not acting on behalf of a Plan or
using the assets of a Plan to effect such purchase or (b) subject to certain
conditions described in the Agreement, that the source of funds used to purchase
this Certificate is an "insurance company general account," or (ii) if such
transferee is a Plan, (a) an opinion of counsel acceptable to and in form and
substance satisfactory to the Master Servicer and the Depositor with respect to
certain matters and (b) such other documentation as the Depositor or the Master
Servicer may require, as described in the Agreement. For purposes of clause (i)
of this paragraph, each person who acquires this certificate or any interest
therein shall be deemed to have made the representations required by the
representation letter referred to in the preceding sentence, unless such person
shall have provided such representation letter or the opinion of counsel
referred to in the preceding sentence to the Depositor and Master Servicer.

            Reference is hereby made to the further provisions of this
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

            This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

            Unless this Certificate has been countersigned by an authorized
officer of the Authenticating Agent, by manual signature, this Certificate shall
not be entitled to any benefit under the Agreement or be valid for any purpose.

<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer

<PAGE>

                                    EXHIBIT C

                [Form of Reverse of Series 2007-17 Certificates]

                    WELLS FARGO ASSET SECURITIES CORPORATION
                       MORTGAGE PASS-THROUGH CERTIFICATES
                                 SERIES 2007-17

            This Certificate is one of a duly authorized issue of Certificates
issued in several Classes designated as Mortgage Pass-Through Certificates of
the Series specified hereon (herein collectively called the "Certificates").

            The Certificates are limited in right of payment to certain
collections and recoveries respecting the Mortgage Loans, all as more
specifically set forth herein and in the Agreement. In the event funds are
advanced with respect to any Mortgage Loan by a Servicer, the Master Servicer or
the Trustee, such advances are reimbursable to such Servicer, the Master
Servicer or the Trustee to the extent provided in the Agreement, from related
recoveries on such Mortgage Loan or from other cash that would have been
distributable to Certificateholders.

            As provided in the Agreement, withdrawals from the Certificate
Account created for the benefit of Certificateholders may be made by the Master
Servicer from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement to a Servicer, the
Master Servicer or the Trustee, as applicable, of advances made by such
Servicer, the Master Servicer or the Trustee.

            The Agreement permits, with certain exceptions therein provided, the
amendment of the Agreement and the modification of the rights and obligations of
the Depositor, the Master Servicer and the Trustee and the rights of the
Certificateholders under the Agreement at any time by the Depositor, the Master
Servicer and the Trustee with the consent of the Holders of Certificates
evidencing in the aggregate not less than 66 2/3% of the Voting Interests of
each Class of Certificates affected thereby. Any such consent by the Holder of
this Certificate shall be conclusive and binding on such Holder and upon all
future holders of this Certificate and of any Certificate issued upon the
transfer hereof or in exchange hereof or in lieu hereof whether or not notation
of such consent is made upon the Certificate. The Agreement also permits the
amendment thereof in certain circumstances without the consent of the Holders of
any of the Certificates.

            As provided in the Agreement and subject to certain limitations
therein set forth, the transfer of this Certificate is registrable in the
Certificate Register upon surrender of this Certificate for registration of
transfer at the office or agency maintained by the Certificate Registrar, duly
endorsed by, or accompanied by an assignment in the form below or other written
instrument of transfer in form satisfactory to the Certificate Registrar, duly
executed by the Holder hereof or such Holder's attorney duly authorized in
writing, and thereupon one or more new Certificates of authorized Denominations
evidencing the same Class and aggregate Percentage Interest will be issued to
the designated transferee or transferees.

            The Certificates are issuable only as registered Certificates
without coupons in Classes and Denominations specified in the Agreement. As
provided in the Agreement and subject to certain limitations therein set forth,
Certificates are exchangeable for new Certificates of authorized Denominations
evidencing the same Class and aggregate Percentage Interest, as requested by the
Holder surrendering the same.

            No service charge will be made for any such registration of transfer
or exchange, but the Certificate Registrar may require payment of a sum
sufficient to cover any tax or other governmental charge payable in connection
therewith.

            The Depositor, the Master Servicer, the Trustee, the Paying Agent
and the Certificate Registrar, and any agent of the Depositor, the Master
Servicer, the Trustee, the Paying Agent or the Certificate Registrar, may treat
the Person in whose name this Certificate is registered as the owner hereof for
all purposes, and neither the Depositor, the Master Servicer, the Trustee, the
Certificate Registrar nor any such agent shall be affected by notice to the
contrary.

            The obligations created by the Agreement in respect of the
Certificates and the Trust Estate created thereby shall terminate upon the last
action required to be taken by the Paying Agent on the Final Distribution Date
pursuant to the Agreement following the earlier of (i) the payment or other
liquidation (or advance with respect thereto) of the last Mortgage Loan subject
thereto or the disposition of all property acquired upon foreclosure or deed in
lieu of foreclosure of any Mortgage Loan, and (ii) the purchase by the Depositor
from the Trust Estate of all remaining Mortgage Loans and all property acquired
in respect of such Mortgage Loans; provided, however, that the Trust Estate will
in no event continue beyond the expiration of 21 years from the death of the
last survivor of the descendants of Joseph P. Kennedy, the late ambassador of
the United States to the Court of St. James, living on the date of the
Agreement. The Agreement permits, but does not require, the Depositor to
purchase all remaining Mortgage Loans and all property acquired in respect of
any Mortgage Loan at a price determined as provided in the Agreement. The
exercise of such option will effect early retirement of the Certificates, the
Depositor's right to exercise such option being subject to the Pool Scheduled
Principal Balance of the Mortgage Loans as of the Distribution Date upon which
the proceeds of such repurchase are distributed being less than ten percent of
the Cut-Off Date Aggregate Principal Balance.

<PAGE>

                                   ASSIGNMENT
                                   ----------

FOR VALUE  RECEIVED,  the undersigned  hereby sell(s),  assign(s) and
transfer(s) unto _______________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
    (Please print or typewrite name and address including postal zip code of
                                    assignee)

the beneficial interest evidenced by the within Mortgage Pass-Through
Certificate and hereby authorizes the transfer of registration of such interest
to assignee on the Certificate Register of the Trust Estate.

            I (We) further direct the Certificate Registrar to issue a new
Certificate of a like Denomination or Percentage Interest and Class, to the
above named assignee and deliver such Certificate to the following address:

________________________________________________________________________________
________________________________________________________________________________

Social Security or other Identifying Number of Assignee:

Dated:

                                      __________________________________________
                                          Signature by or on behalf of assignor

                                      __________________________________________
                                          Signature Guaranteed

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

            The assignee should include the following for purposes of
distribution:

            Distributions shall be made by wire transfer or otherwise, in
immediately available funds to _________________________________________ for the
account of ______________________________________________________ account number
_____________, or, if mailed by check, to ______________________________________
_______________________________________________________. Applicable statements
should be mailed to ___________________________________________.

            This information is provided by ______________________, the assignee
named above, or ___________________________________, as its agent.

<PAGE>

                                    EXHIBIT D

                                    RESERVED

<PAGE>

                                    EXHIBIT E

                               CUSTODIAL AGREEMENT
                               -------------------

            THIS CUSTODIAL AGREEMENT (as amended and supplemented from time to
time, the "Agreement"), dated as of December 20, 2007, by and among HSBC BANK
USA, NATIONAL ASSOCIATION, not individually, but solely as Trustee (including
its successors under the Pooling and Servicing Agreement defined below, the
"Trustee"), WELLS FARGO ASSET SECURITIES CORPORATION (together with any
successor in interest, the "Depositor"), WELLS FARGO BANK, N.A. (together with
any successor in interest or successor under the Pooling and Servicing Agreement
referred to below, the "Master Servicer") and WELLS FARGO BANK, N.A. (together
with any successor in interest or any successor appointed hereunder, the
"Custodian").

                           W I T N E S S E T H  T H A T
                           -------------------  -------

            WHEREAS, the Depositor, the Master Servicer, and the Trustee, have
entered into a Pooling and Servicing Agreement dated as of December 20, 2007
relating to the issuance of Mortgage Pass-Through Certificates, Series 2007-17
(as amended and supplemented from time to time, the "Pooling and Servicing
Agreement"); and

            WHEREAS, the Custodian has agreed to act as agent for the Trustee
for the purposes of receiving and holding certain documents and other
instruments delivered by the Depositor under the Pooling and Servicing
Agreement, all upon the terms and conditions and subject to the limitations
hereinafter set forth;

            NOW, THEREFORE, in consideration of the premises and the mutual
covenants and agreements hereinafter set forth, the Trustee, the Depositor, the
Master Servicer and the Custodian hereby agree as follows:

                                    ARTICLE I

                                   Definitions

            Capitalized terms used in this Agreement and not defined herein
shall have the meanings assigned in the Pooling and Servicing Agreement, unless
otherwise required by the context herein.

                                   ARTICLE II

                          Custody of Mortgage Documents

            Section 2.1. Custodian to Act as Agent; Acceptance of Custodial
Files. Subject to Section 2.3 hereof, the Custodian, as the duly appointed agent
of the Trustee for these purposes, declares that it holds and will hold the
documents delivered to it pursuant to Section 2.01 of the Pooling and Servicing
Agreement and any other documents constituting part of the Owner Mortgage Loan
File or Retained Mortgage Loan File received on or subsequent to the date hereof
(the "Custodial Files") as agent for the Trustee, in trust, for the use and
benefit of all present and future Certificateholders. The Depositor shall give
written notice to the Custodian within 10 business days of the occurrence of a
Document Transfer Event.

            Section 2.2. Recordation of Assignments. Unless an assignment of a
Mortgage is not required to be recorded in accordance with Section 2.01 of the
Pooling and Servicing Agreement, if any Custodial File includes one or more
assignments to the Trustee of Mortgage Notes that have not been recorded, each
such assignment shall be delivered by the Custodian to the Depositor for the
purpose of recording it in the appropriate public office for real property
records, and the Depositor, at no expense to the Custodian, shall promptly cause
to be recorded in the appropriate public office for real property records each
such assignment and, upon receipt thereof from such public office, shall return
each such assignment to the Custodian.

            Section 2.3. Review of Custodial Files. The Custodian agrees, for
the benefit of Certificateholders, to review, in accordance with the provisions
of Section 2.02 of the Pooling and Servicing Agreement, each Custodial File and
to provide the initial and final certifications in the forms of Exhibits N and O
to the Pooling and Servicing Agreement in accordance with the provisions
thereof. If in performing the review required by this Section 2.3 the Custodian
finds any document or documents constituting a part of a Custodial File to be
missing or defective, the Custodian shall follow the procedures specified in the
Pooling and Servicing Agreement.

            Section 2.4. Notification of Breaches of Representations and
Warranties. Upon discovery by the Custodian of a breach of any representation or
warranty made by the Depositor or the Master Servicer as set forth in the
Pooling and Servicing Agreement, the Custodian shall follow the procedures
specified in the Pooling and Servicing Agreement.

            Section 2.5. Custodian to Cooperate; Release of Custodial Files.
Upon the payment in full of any Mortgage Loan, or the receipt by the Master
Servicer of a notification that payment in full will be escrowed in a manner
customary for such purposes, the Master Servicer or applicable Servicer shall
immediately deliver to the Custodian two copies of a Request for Release or such
request in an electronic format acceptable to the Custodian and shall request
delivery to it of the Custodial File. The Custodian agrees, within five business
days of receipt of such Request for Release, to release the related Custodial
File to the Master Servicer or applicable Servicer.

            From time to time as is appropriate for the servicing or foreclosure
of any Mortgage Loan, the Master Servicer or applicable Servicer shall deliver
to the Custodian two copies of a Request for Release of a Servicing Officer
requesting that possession of the Custodial File be released to the Servicer or
Master Servicer and certifying as to the reason for such release. Upon receipt
of the foregoing, the Custodian shall deliver the Custodial File to the Master
Servicer or applicable Servicer. The Master Servicer or applicable Servicer
shall cause each Custodial File therein so released to be returned to the
Custodian when the need therefor by the Master Servicer or applicable Servicer
no longer exists, unless (i) the Mortgage Loan has been liquidated and the
Liquidation Proceeds relating to the Mortgage Loan have been deposited in the
Certificate Account to the extent required by the Pooling and Servicing
Agreement or (ii) the Custodial File or such document has been delivered to an
attorney, or to a public trustee or other public official as required by law,
for purposes of initiating or pursuing legal action or other proceedings for the
foreclosure of the Mortgaged Property either judicially or non-judicially. In
the event of the liquidation of a Mortgage Loan, the Master Servicer or
applicable Servicer shall deliver two copies of a Request for Release with
respect thereto to the Custodian upon deposit of the related Liquidation
Proceeds in the Certificate Account to the extent required by the Pooling and
Servicing Agreement.

            The Custodian shall maintain records (i) identifying all requests
made by Servicers or the Master Servicer (other than requests relating to
Custodial Files already released by the Custodian) for the release by the
Custodian of Custodial Files with respect to the Mortgage Loans and (ii) all
Custodial Files released by the Custodian.

            Section 2.6. Assumption Agreements. In the event that any assumption
agreement or substitution of liability agreement is entered into with respect to
any Mortgage Loan subject to this Agreement in accordance with the terms and
provisions of the Pooling and Servicing Agreement, the Master Servicer shall
notify the Custodian that such assumption or substitution agreement has been
completed by forwarding to the Custodian the original of such assumption or
substitution agreement, which copy shall be added to the related Custodial File
and, for all purposes, shall be considered a part of such Custodial File to the
same extent as all other documents and instruments constituting parts thereof.

                                   ARTICLE III

                            Concerning the Custodian

            Section 3.1. Custodian a Bailee and Agent of the Trustee. With
respect to each Mortgage Note, Mortgage and other documents constituting each
Custodial File which are delivered to the Custodian, the Custodian is
exclusively the bailee and agent of the Trustee, holds such documents for the
benefit of Certificateholders and undertakes to perform such duties and only
such duties as are specifically set forth in this Agreement and in the Pooling
and Servicing Agreement. All provisions of the Pooling and Servicing Agreement
setting forth duties of the Custodian in more detail are hereby incorporated by
reference into this Agreement. Except upon compliance with the provisions of
Section 2.5 of this Agreement and the provisions of the Pooling and Servicing
Agreement, no Mortgage Note or other document constituting a part of a Custodial
File shall be delivered by the Custodian to the Depositor or the Master Servicer
or otherwise released from the possession of the Custodian.

            Section 3.2. Indemnification. The Depositor hereby agrees to
indemnify and hold the Custodian harmless from and against all claims,
liabilities, losses, actions, suits or proceedings at law or in equity, or any
other expenses, fees or charges of any character or nature, which the Custodian
may incur or with which the Custodian may be threatened by reasons of its acting
as custodian under this Agreement, including indemnification of the Custodian
against any and all expenses, including attorney's fees if counsel for the
Custodian has been approved by the Depositor, and the cost of defending any
action, suit or proceedings or resisting any claim. Notwithstanding the
foregoing, it is specifically understood and agreed that in the event any such
claim, liability, loss, action, suit or proceeding or other expense, fees, or
charge shall have been caused by reason of any negligent act, negligent failure
to act, or willful misconduct on the part of the Custodian, or which shall
constitute a willful breach of its duties hereunder, the indemnification
provisions of this Agreement shall not apply.

            Section 3.3. Custodian May Own Certificates. The Custodian in its
individual or any other capacity may become the owner or pledgee of Certificates
with the same rights it would have if it were not Custodian.

            Section 3.4. Master Servicer to Pay Custodian's Fees and Expenses.
The Master Servicer covenants and agrees to pay to the Custodian from time to
time, and the Custodian shall be entitled to, reasonable compensation for all
services rendered by it in the exercise and performance of any of the powers and
duties hereunder of the Custodian, and the Master Servicer will pay or reimburse
the Custodian upon its request for all reasonable expenses, disbursements and
advances incurred or made by the Custodian in accordance with any of the
provisions of this Agreement (including the reasonable compensation and the
expenses and disbursements of its counsel and of all persons not regularly in
its employ), except any such expense, disbursement or advance as may arise from
its negligence or bad faith. The Master Servicer's obligations regarding
payments due to the Custodian pursuant to this Section 3.4 shall survive the
termination of this Agreement with respect to any fees and expenses due
hereunder.

            Section 3.5. Custodian May Resign; Trustee May Remove Custodian. The
Custodian, upon 30 days written notice to the Depositor, the Master Servicer and
the Trustee, may resign from the obligations and duties hereby imposed upon it
as such obligations and duties relate to its acting as Custodian of the Mortgage
Loans. Upon receiving such notice of resignation, the Trustee shall either take
custody of the Custodial Files itself and give prompt notice thereof to the
Depositor, the Master Servicer and the Custodian or promptly appoint a successor
Custodian by written instrument, in duplicate, one copy of which instrument
shall be delivered to the resigning Custodian and one copy to the successor
Custodian. If the Trustee shall not have taken custody of the Custodial Files
and no successor Custodian shall have been so appointed and have accepted
resignation, the resigning Custodian may petition any court of competent
jurisdiction for the appointment of a successor Custodian.

            The Trustee, upon 60 days written notice to the Depositor, the
Master Servicer and the Custodian, may remove the Custodian. In such event, the
Trustee shall appoint, or petition a court of competent jurisdiction to appoint,
a successor Custodian hereunder. Any successor Custodian shall be a depository
institution subject to supervision or examination by federal or state authority
and shall be able to satisfy the other requirements contained in Section 3.7.

            Any resignation or removal of the Custodian and appointment of a
successor Custodian pursuant to any of the provisions of this Section 3.5 shall
become effective upon acceptance of appointment by the successor Custodian. The
Trustee shall give prompt notice to the Depositor and the Master Servicer of the
appointment of any successor Custodian. No successor Custodian shall have been
appointed and accepted appointment by the Trustee without the prior approval of
the Depositor and the Master Servicer.

            Section 3.6. Merger or Consolidation of Custodian. Any Person into
which the Custodian may be merged or converted or with which it may be
consolidated, or any Person resulting from any merger, conversion or
consolidation to which the Custodian shall be a party, or any Person succeeding
to the business of the Custodian, shall be the successor of the Custodian
hereunder, without the execution or filing of any paper or any further act on
the part of any of the parties hereto, anything herein to the contrary
notwithstanding.

            The Custodian and such successor or surviving Person shall notify
the Depositor, the Master Servicer and the Trustee of any such merger,
conversion or consolidation at least two Business Days prior to the effective
date thereof and shall provide the Depositor and the Master Servicer with all
information required by the Depositor to comply with its reporting obligations
not later than the effective date of such merger, conversion or consolidation
(unless giving prior notice would be prohibited by applicable law or by a
confidentiality agreement, in which case notice shall be given by 12 noon
eastern time one Business Day after such merger or consolidation).

            Section 3.7. Representations of the Custodian. The Custodian hereby
represents that it is a depository institution subject to supervision or
examination by a federal or state authority, has a combined capital and surplus
of at least $10,000,000 and is qualified to do business in the jurisdiction in
which it will hold any Custodial File.

            Section 3.8. Limitations on the Responsibilities of the Custodian.

            (a) Neither the Custodian nor any of its Affiliates, directors,
officers, agents, counsel, attorneys-in-fact, and employees shall be liable for
any action or omission to act hereunder except for its own or such person's
gross negligence or willful misconduct. Notwithstanding the foregoing sentence,
in no event shall the Custodian or its Affiliates, directors, officers, agents,
counsel, attorneys-in-fact, and employees be held liable for any special,
indirect, punitive or consequential damages resulting from any action taken or
omitted to be taken by it or them hereunder or in connection herewith even if
advised of the possibility of such damages. The provisions of this Section 3.8
shall survive the resignation or removal of the Custodian and the termination of
this Agreement.

            (b) The Custodian shall not be responsible for preparing or filing
any reports or returns relating to federal, state or local income taxes with
respect to this Agreement, other than for the Custodian's compensation or for
reimbursement of expenses.

            (c) The Custodian shall not be responsible or liable for, and makes
no representation or warranty with respect to, the validity, adequacy or
perfection of any lien upon or security interest in any Mortgage File.

            (d) The Custodian shall not be responsible for delays or failures in
performance resulting from acts beyond its control. Such acts shall include, but
not be limited to, acts of God, strikes, lockouts, riots, acts of war or
terrorism, epidemics, nationalization, expropriation, currency restrictions,
governmental regulations superimposed after the fact, fire, communication line
failures, computer viruses, power failures, earthquakes or other disasters.

            (e) The duties and obligations of the Custodian shall only be such
as are expressly set forth in this Agreement and the Pooling and Servicing
Agreement or as set forth in a written amendment to this Agreement or the
Pooling and Servicing Agreement executed by the parties hereto or their
successors and assigns. In the event that any provision of this Agreement
implies or requires that action or forbearance be taken by a party, but is
silent as to which party has the duty to act or refrain from acting, the parties
agree that the Custodian shall not be the party required to take the action or
refrain from acting. In no event shall the Custodian have any responsibility to
ascertain or take action except as expressly provided herein.

            (f) Nothing in this Agreement shall be deemed to impose on the
Custodian any duty to qualify to do business in any jurisdiction, other than (i)
any jurisdiction where any Mortgage File is or may be held by the Custodian from
time to time hereunder, and (ii) any jurisdiction where its ownership of
property or conduct of business requires such qualification and where failure to
qualify could have a material adverse effect on the Custodian or its property or
business or on the ability of the Custodian to perform it duties hereunder.

            (g) The Custodian shall have no duty to ascertain whether or not any
cash amount or payment has been received by the Trustee, the Depositor, the
Master Servicer, or any third person.

                                   ARTICLE IV

           Documents and Notices Required to be Delivered by Custodian

            Section 4.1 Assessment of Servicing Compliance; Registered Public
Accounting Firm Attestation Reports; Exchange Act Reporting.

            (a) The Custodian shall furnish, or cause to be furnished in the
case of clause (iii), to the Master Servicer, no later than March 5 of each year
or if such day is not a Business Day, the next Business Day (with a 10 calendar
day cure period, but in no event later than March 15), commencing in March 2008,
the following:

            (i) a report (in form and substance reasonably satisfactory to the
      Master Servicer and the Depositor) regarding the Custodian's assessment of
      compliance with the Servicing Criteria applicable to it during the
      immediately preceding calendar year, as required under Rules 13a-18 and
      15d-18 of the Exchange Act and Item 1122 of Regulation AB. Such report
      shall be addressed to the Master Servicer and signed by an authorized
      officer of the Custodian, and shall address, at a minimum, each of the
      Servicing Criteria applicable to the Custodian, as specified in the table
      in Exhibit R to the Pooling and Servicing Agreement;

            (ii) a report of a registered public accounting firm reasonably
      acceptable to the Master Servicer and the Depositor that attests to, and
      reports on, the assessment of compliance made by the Custodian and
      delivered pursuant to the preceding paragraph. Such attestation shall be
      in accordance with Rules 1-02(a)(3) and 2-02(g) of Regulation S-X under
      the Securities Act and the Exchange Act. If requested by the Master
      Servicer or the Depositor, such report shall contain or be accompanied by
      a consent of such accounting firm to inclusion or incorporation of such
      report in the Depositor's Registration Statement on Form S-3 relating to
      the Certificates and the Trust's Form 10-K; and

            (iii) an assessment of compliance and accountants' attestation as
      described in paragraphs (i) and (ii) of this Section 4.1(a) with respect
      to each Subcontractor determined by the Custodian pursuant to Section 4.2
      to be "participating in the servicing function" within the meaning of Item
      1122 of Regulation AB.

            An assessment of compliance provided by a Subcontractor pursuant to
Section 4.1(a)(iii) need not address any elements of the Servicing Criteria
applicable to it other than those specified by the Custodian pursuant to Section
4.2.

            No later than 30 days following the end of each fiscal year for the
Trust for which a Form 10-K is required to be filed, the Custodian shall forward
to the Master Servicer the name of each Subcontractor engaged by it and what
Relevant Servicing Criteria will be addressed in the report on assessment of
compliance prepared by such Subcontractor. When the Custodian submits its
assessment to the Master Servicer, it will also at such time include the
assessment (and attestation pursuant to Section 4.1(a)(ii) hereof) of each
Subcontractor engaged by it.

            (b) Within five (5) calendar days after a Distribution Date, the
Custodian shall provide to the Master Servicer, to the extent known, in
EDGAR-compatible format, or in such other form as otherwise agreed upon by the
Master Servicer and the Custodian, the form and substance of any Additional Form
10-D Disclosure applicable to the Custodian, as indicated in the table in
Exhibit S to the Pooling and Servicing Agreement. The Custodian acknowledges
that the performance by the Master Servicer of its duties under Section 3.12(a)
of the Pooling and Servicing Agreement relating to the timely preparation and
filing of Form 10-D is contingent upon the Custodian strictly observing all
applicable deadlines in the performance of its duties under this Section 4.1(b).

            (c) No later than March 5 (with a 10 calendar day cure period, but
in no event later than March 15) of each year that the Trust is subject to the
Exchange Act reporting requirements, commencing in March 2008, the Custodian
shall provide to the Master Servicer, to the extent known, in EDGAR-compatible
format, or in such other form as otherwise agreed upon by the Master Servicer
and the Custodian, the form and substance of any Additional Form 10-K Disclosure
applicable to the Custodian, as indicated in the table in Exhibit T to the
Pooling and Servicing Agreement. The Custodian acknowledges that the performance
by the Master Servicer of its duties under Section 3.12(b) of the Pooling and
Servicing Agreement relating to the timely preparation and filing of Form 10-K
is contingent upon the Custodian strictly observing all applicable deadlines in
the performance of its duties under this Section 4.1(c).

            (d) For so long as the Trust is subject to the Exchange Act
reporting requirements, no later than the end of business on the second Business
Day after the occurrence of a Reportable Event applicable to the Custodian, the
Custodian shall provide to the Master Servicer, to the extent known, in
EDGAR-compatible format, or in such other form as otherwise agreed upon by the
Master Servicer and the Custodian, the form and substance of any Form 8-K
Disclosure Information applicable to the Custodian, as indicated in the table in
Exhibit U to the Pooling and Servicing Agreement. The Custodian acknowledges
that the performance by the Master Servicer of its duties under Section 3.12(c)
of the Pooling and Servicing Agreement relating to the timely preparation and
filing of Form 8-K is contingent upon the Custodian strictly observing all
applicable deadlines in the performance of its duties under this Section 4.1(d).

            (e) The Custodian shall indemnify the Master Servicer, each
affiliate of the Master Servicer, the Trust, each broker dealer acting as
underwriter or initial purchaser of the Certificates, each Person who controls
any of such parties and the Depositor (within the meaning of Section 15 of the
Securities Act and Section 20 of the Exchange Act); and the respective present
and former directors, officers, employees and agents of each of the foregoing
and of the Depositor (each such entity, an "Indemnified Party"), and shall hold
each of them harmless from and against any losses, damages, penalties, fines,
forfeitures, legal fees and expenses and related costs, judgments, and any other
costs, fees and expenses that any of them may sustain arising out of or based
upon:

                  (i) (A) any untrue statement of a material fact contained or
            alleged to be contained in any information, report, certification,
            accountants' letter or other material provided in written or
            electronic form under this Section 4.1 or Section 4.2 hereof by or
            on behalf of the Custodian, or provided under Sections 4.1 or 4.2 by
            or on behalf of any Subcontractor (collectively, the "Custodian
            Information"), or (B) the omission or alleged omission to state in
            the Custodian Information a material fact required to be stated in
            the Custodian Information or necessary in order to make the
            statements therein, in the light of the circumstances under which
            they were made, not misleading; provided, by way of clarification,
            that clause (B) of this paragraph shall be construed solely by
            reference to the Custodian Information and not to any other
            information communicated in connection with a sale or purchase of
            securities, without regard to whether the Custodian Information or
            any portion thereof is presented together with or separately from
            such other information; or

                  (ii) any failure by the Custodian or any Subcontractor engaged
            by the Custodian to deliver any information, report, certification,
            accountants' letter or other material when and as required under
            Sections 4.1 or 4.2, including any failure by the Custodian to
            identify pursuant to Section 4.2 any Subcontractor "participating in
            the servicing function" within the meaning of Item 1122 of
            Regulation AB.

      In the case of any failure of performance described in clause (ii) of this
Section, the Custodian shall promptly reimburse the Master Servicer and the
Depositor, as applicable, for all costs reasonably incurred by each such party
in order to obtain the information, report, certification, accountants' letter
or other material not delivered as required by the Custodian or any
Subcontractor. If the indemnification provided for herein is unavailable to hold
harmless any Indemnified Party, then the Custodian agrees that it shall
contribute to the amount paid or payable by such Indemnified Party as a result
of the losses, claims, damages or liabilities of such Indemnified Party in such
proportion as is appropriate to reflect the relative fault of such Indemnified
Party on the one hand and the Custodian on the other in connection with a breach
of the Custodian's obligations under this Section 4.1 or the Custodian's
negligence, bad faith or willful misconduct in connection therewith.

            4.2 Engagement of Affiliates or Third-Parties. The Custodian shall
not hire or otherwise utilize the services of any Subcontractor to fulfill any
of the obligations of the Custodian as servicer under this Agreement unless the
Custodian complies with the provisions of this Section.

            It shall not be necessary for the Custodian to seek the consent of
the Master Servicer or the Depositor to the utilization of any Subcontractor.
The Custodian shall promptly upon request provide to the Master Servicer (or any
designee of Master Servicer) a written description (in form and substance
satisfactory to the Master Servicer and the Depositor) of the role and function
of each Subcontractor utilized by the Custodian, specifying (i) the identity of
each such Subcontractor, (ii) which (if any) of such Subcontractors are
"participating in the servicing function" within the meaning of Item 1122 of
Regulation AB, and (iii) which elements of the Servicing Criteria will be
addressed in assessments of compliance provided by each Subcontractor identified
pursuant to clause (ii) of this paragraph.

            As a condition to the utilization of any Subcontractor determined to
be "participating in the servicing function" within the meaning of Item 1122 of
Regulation AB, the Custodian shall cause any such Subcontractor used by the
Custodian, for the benefit of the Master Servicer and the Depositor to comply
with the provisions of Section 4.1 of this Agreement to the same extent as if
such Subcontractor were the Custodian. The Custodian shall be responsible for
obtaining from each Subcontractor and delivering to the Master Servicer any
assessment of compliance and attestation required to be delivered by such
Subcontractor under Section 4.1, in each case as and when required to be
delivered.

            4.3 Errors and Omissions Policy. The Custodian shall maintain, at
all times and at its own expense, an insurance policy covering losses caused by
errors or omissions of the Custodian and its personnel (such policy, an "Errors
and Omissions Policy"), which policy shall have such terms and coverage amounts
as are comparable to those of errors and omissions policies maintained by
custodians of mortgage loans generally.

            The Errors and Omissions Policy shall insure the Custodian, its
successors and assigns, against any losses resulting from negligence, errors or
omissions on the part of officers, employees or other persons acting on behalf
of the Custodian in the performance of its duties as Custodian pursuant to this
Agreement.

            The Custodian shall maintain in effect the Errors and Omissions
Policy at all times and the Errors and Omissions Policy may not be canceled,
permitted to lapse or otherwise terminated without the acquisition of comparable
coverage by the Custodian.

            4.4 Compliance with Article IV. If (a) the Custodian fails to comply
with its obligations to deliver any assessment of servicing compliance or
registered public accounting firm attestation reports required pursuant to this
Article IV or (b) any Subcontractor engaged by the Custodian fails to comply
with its obligations to deliver any assessment of servicing compliance or
registered public accounting firm attestation reports, the Master Servicer, may,
after consultation with the Depositor, remove the Custodian and appoint a
successor custodian by written instrument, in duplicate, one copy of which
instrument shall be delivered to the Custodian so removed and one copy to the
successor custodian.

                                    ARTICLE V

                            Miscellaneous Provisions

            Section 5.1. Notices. All notices, requests, consents and demands
and other communications required under this Agreement, or pursuant to any other
instrument or document delivered hereunder shall be in writing and, unless
otherwise specifically provided, may be delivered personally, by telegram or
telex, or by registered or certified mail, postage prepaid, return receipt
requested, at the addresses specified on the signature page hereof (unless
changed by the particular party whose address is stated herein by similar notice
in writing), in which case the notice will be deemed delivered when received.

            Section 5.2. Amendments. No modification or amendment of or
supplement to this Agreement shall be valid or effective unless the same is in
writing and signed by all parties hereto, and neither the Depositor, the Master
Servicer nor the Trustee shall enter into any amendment hereof except as
permitted by the Pooling and Servicing Agreement. The Trustee shall give prompt
written notice to the Custodian of any amendment or supplement to the Pooling
and Servicing Agreement and furnish the Custodian with written copies thereof.

            Section 5.3. Governing Law. This Agreement shall be deemed a
contract made under the laws of the State of New York and shall be construed and
enforced in accordance with and governed by the laws of the State of New York.

            Section 5.4. Recordation of Agreement. To the extent permitted by
applicable law, this Agreement is subject to recordation in all appropriate
public offices for real property records in all the counties or other comparable
jurisdictions in which any or all of the properties subject to the Mortgages are
situated, and in any other appropriate public recording office or elsewhere,
such recordation to be effected by the Master Servicer and at its expense on
direction by the Trustee, but only upon direction accompanied by an Opinion of
Counsel to the effect that such recordation materially and beneficially affects
the interests of the Certificateholders.

            For the purpose of facilitating the recordation of this Agreement as
herein provided and for other purposes, this Agreement may be executed
simultaneously in any number of counterparts, each of which counterparts shall
be deemed to be an original, and such counterparts shall constitute but one and
the same instrument.

            Section 5.5. Severability of Provisions. If any one or more of the
covenants, agreements, provisions or terms of this Agreement shall be for any
reason whatsoever held invalid, then such covenants, agreements, provisions or
terms shall be deemed severable from the remaining covenants, agreements,
provisions or terms of this Agreement and shall in no way affect the validity or
enforceability of the other provisions of this Agreement or of the Certificates
or the rights of the holders thereof.

            Section 5.6. Regulation AB Compliance; Intent of Parties;
Reasonableness. The parties hereto acknowledge that interpretations of the
requirements of Regulation AB may change over time, whether due to interpretive
guidance provided by the Commission or its staff, consensus among participants
in the asset-backed securities markets, advice of counsel, or otherwise, and
agree to comply with requests made by the Depositor or the Master Servicer in
good faith for delivery of information under these provisions on the basis of
evolving interpretations of Regulation AB. In connection with the Trust, the
parties hereto shall cooperate fully with the Master Servicer and the Depositor
to deliver to the Master Servicer and/or the Depositor (including its assignees
or designees), any and all statements, reports, certifications, records and any
other information available to such party and reasonably necessary in the good
faith determination of the Depositor or the Master Servicer to permit the
Depositor or the Master Servicer to comply with the provisions of Regulation AB,
together with such disclosures reasonably believed by the Depositor or the
Master Servicer to be necessary in order to effect such compliance.

<PAGE>

            IN WITNESS WHEREOF, this Agreement is executed as of the date first
above written.

Address:                              HSBC BANK USA, NATIONAL ASSOCIATION,
                                         as Trustee

452 Fifth Avenue
New York, New York 10018              By:
                                         ---------------------------------------
                                      Name:  Alexander Pabon
                                      Title: Vice President

Address:                              WELLS FARGO ASSET SECURITIES CORPORATION,
                                         as Depositor

5325 Spectrum Drive
Frederick, Maryland 21703             By:
                                         ---------------------------------------
                                      Name:  Bradley A. Davis
                                      Title: Vice President

Address:                              WELLS FARGO BANK, N.A.,
                                         as Master Servicer

9062 Old Annapolis Road
Columbia, Maryland 21045              By:
                                         ---------------------------------------
                                      Name:  Christopher Furlow
                                      Title: Assistant Vice President

Address:                              WELLS FARGO BANK, N.A.,
                                         as Custodian

1015 10th Avenue South East
Minneapolis, Minnesota 55414          By:
                                         ---------------------------------------
                                         Name:  Mary B. Hogan
                                         Title: Vice President

<PAGE>

STATE OF MARYLAND       )
                        ss.:
COUNTY OF FREDERICK     )

            On this 20th day of December, 2007, before me, a notary public in
and for the State of Maryland, personally appeared Bradley A. Davis, known to me
who, being by me duly sworn, did depose and say that he resides at Cooksville,
Maryland; that he is a Vice President of Wells Fargo Asset Securities
Corporation, a Delaware corporation, one of the parties that executed the
foregoing instrument; and that he signed his name thereto by order of the Board
of Directors of said corporation.

_________________________
Notary Public

[NOTARIAL SEAL]

<PAGE>

STATE OF MARYLAND       )
                        ss.:
COUNTY OF HOWARD        )

            On this 20th day of December, 2007, before me, the undersigned
officer, personally appeared Christopher Furlow, and acknowledged to me to be an
Assistant Vice President of Wells Fargo Bank, National Association, and that as
such officer, being duly authorized to do so pursuant to such entity's by-laws
or a resolution of its board of directors, executed and acknowledged the
foregoing instrument for the purposes therein contained, by signing the name of
such entity by himself as such officer as his free and voluntary act and deed
and the free and voluntary act and deed and the free and voluntary act and deed
of said entity.

            IN WITNESS WHEREOF, I hereunto set my hand and official seal.

_________________________
Notary Public

[NOTARIAL SEAL]

<PAGE>

STATE OF NEW YORK       )
                        ss.:
COUNTY OF NEW YORK      )

            On this 20th day of December, 2007, before me, a notary public in
and for the State of New York, personally appeared Alexander Pabon, known to me
who, being by me duly sworn, did depose and say that he is a Vice President of
HSBC Bank USA, National Association, a national banking association, one of the
parties that executed the foregoing instrument; and that he signed his name
thereto by order of the Board of Directors of said association.

_________________________
Notary Public

[NOTARIAL SEAL]

<PAGE>

STATE OF MINNESOTA      )
                        ss.:
COUNTY OF HENNEPIN      )

            On this 20th day of December, 2007, before me, a notary public in
and for the State of Minnesota, personally appeared Mary B. Hogan, known to me
who, being by me duly sworn, did depose and say that she is a Vice President of
Wells Fargo Bank, N.A., a national banking association, one of the parties that
executed the foregoing instrument; and that she signed her name thereto by order
of the Board of Directors of said association.

_________________________
Notary Public

[NOTARIAL SEAL]

<PAGE>

                                    EXHIBIT F

                 Addresses for Requesting Mortgage Loan Schedule

In the case of the Depositor:

Wells Fargo Asset Securities Corporation
5325 Spectrum Drive
Frederick, Maryland 21703
Attention: Vice President - Structured Finance

In the case of the Master Servicer:

Wells Fargo Bank, N.A.
9062 Old Annapolis Road
Columbia, Maryland 21045-1951
Attention: Corporate Trust Services - WFMBS 2007-17

<PAGE>

                                    EXHIBIT G

                        REQUEST FOR RELEASE OF DOCUMENTS

To:   Wells Fargo Bank, N.A.
      1015 10th Avenue S.E.
      Minneapolis., MN  55414
      Attn:  ________________

      Re:   Custodial Agreement, dated as of December 20, 2007, among HSBC Bank
            USA, National Association, as Trustee, Wells Fargo Asset Securities
            Corporation, as Depositor, Wells Fargo Bank, N.A., as Master
            Servicer, and Wells Fargo Bank, N.A., as Custodian, relating to the
            Wells Fargo Asset Securities Corporation; Mortgage Pass-Through
            Certificates, Series 2007-17.
            -----------------------------

            In connection with the administration of the Mortgage Loans held by
you as Custodian for the Trust Estate pursuant to the above-captioned Custodial
Agreement, we request the release, and hereby acknowledge receipt, of the
Custodian's Owner Mortgage Loan File for the Mortgage Loan described below, for
the reason indicated.

                              Mortgage Loan Number:
                              ---------------------

                       Mortgagor Name, Address & Zip Code:
                       -----------------------------------

            Reason for Requesting Documents (check one):

            ____________      1.    Mortgage Paid in Full

            ____________      2.    Foreclosure

            ____________      3.    Substitution

            ____________      4.    Other Liquidation (Repurchases, etc.)

            ____________      5.    Nonliquidation

            Reason:___________________________________

            By:_______________________________________
                 (authorized signer)

            Issuer:___________________________________

            Address:__________________________________

            __________________________________________

            Date:_____________________________________

                                    Custodian
                                    ---------

Wells Fargo Bank, N.A.

            Please acknowledge the execution of the above request by your
signature and date below:

____________________________________                  _________________
Signature                                             Date

Documents returned to Custodian:

____________________________________                  _________________
Custodian                                             Date

<PAGE>

                                    EXHIBIT H

                                            AFFIDAVIT PURSUANT TO SECTION
                                            860E(e)(4) OF THE INTERNAL REVENUE
                                            CODE OF 1986, AS AMENDED, AND FOR
                                            NON-ERISA INVESTORS

STATE OF                )
                        )  ss.:
COUNTY OF               )

             [NAME OF OFFICER], being first duly sworn, deposes and says:

            1. That he is [Title of Officer] of [Name of Purchaser] (the
"Purchaser"), a [description of type of entity] duly organized and existing
under the laws of the [State of ] [United States], on behalf of which he makes
this affidavit.

            2. That the Purchaser's Taxpayer Identification Number is [ ].

            3. That the Purchaser is not a "disqualified organization" within
the meaning of Section 860E(e)(5),of the Internal Revenue Code of 1986, as
amended (the "Code"), or an ERISA Prohibited Holder, and will not be a
"disqualified organization" or an ERISA Prohibited Holder, as of [date of
transfer], and that the Purchaser is not acquiring Wells Fargo Asset Securities
Corporation Mortgage Pass-Through Certificates, Series 2007-17, Class A-R
Certificate (the "Residual Certificate") for the account of, or as agent
(including a broker, nominee, or other middleman) for, any person or entity from
which it has not received an affidavit substantially in the form of this
affidavit. For these purposes, a "disqualified organization" means the United
States, any state or political subdivision thereof, any foreign government, any
international organization, any agency or instrumentality of any of the
foregoing (other than an instrumentality if all of its activities are subject to
tax and a majority of its board of directors is not selected by such
governmental entity), any cooperative organization furnishing electric energy or
providing telephone service to persons in rural areas as described in Code
Section 1381(a)(2)(C), or any organization (other than a farmers' cooperative
described in Code Section 521) that is exempt from taxation under the Code
unless such organization is subject to the tax on unrelated business income
imposed by Code Section 511. For these purposes, an "ERISA Prohibited Holder"
means an employee benefit plan or other retirement arrangement subject to Title
I of the Employee Retirement Income Security Act of 1974, as amended ("ERISA"),
or Code Section 4975 or a governmental plan, as defined in Section 3(32) of
ERISA, subject to any federal, state or local law which is, to a material
extent, similar to the foregoing provisions of ERISA or the Code (collectively,
a "Plan") or a Person acting on behalf of or investing the assets of such a
Plan.

            4. That the Purchaser historically has paid its debts as they have
come due and intends to pay its debts as they come due in the future and the
Purchaser intends to pay taxes associated with holding the Residual Certificate
as they become due.

            5. That the Purchaser understands that it may incur tax liabilities
with respect to the Residual Certificate in excess of cash flows generated by
the Residual Certificate.

            6. That the Purchaser will not transfer the Residual Certificate to
any person or entity from which the Purchaser has not received an affidavit
substantially in the form of this affidavit and as to which the Purchaser has
actual knowledge that the requirements set forth in paragraph 3, 4 or 10 hereof
are not satisfied or that the Purchaser has reason to know does not satisfy the
requirements set forth in paragraph 4 hereof.

            7. That the Purchaser is aware that the Residual Certificate may be
a "noneconomic residual interest" within the meaning of Treasury regulations
promulgated pursuant to the Code and that the transferor of a noneconomic
residual interest will remain liable for any taxes due with respect to the
income on such residual interest, unless no significant purpose of the transfer
was to impede the assessment or collection of tax.

            8. That the Purchaser will not cause income from the Residual
Certificate to be attributable to a foreign permanent establishment or fixed
base, within the meaning of an applicable income tax treaty, of the Purchaser or
any other person.

            9. That, if the Purchaser is purchasing the Residual Certificate in
a transfer intended to meet the safe harbor provisions of Treasury Regulations
Sections 1.860E-1(c), the Purchaser has completed and attached Attachment A
hereto.

            10. That the Purchaser (i) is a U.S. Person or (ii) is a person
other than a U.S. Person (a "Non-U.S. Person") that holds the Residual
Certificate in connection with the conduct of a trade or business within the
United States and has furnished the transferor and the Master Servicer with an
effective Internal Revenue Service Form W-8ECI or successor form at the time and
in the manner required by the Code or (iii) is a Non-U.S. Person that has
delivered to both the transferor and the Master Servicer an opinion of a
nationally recognized tax counsel to the effect that the transfer of the
Residual Certificate to it is in accordance with the requirements of the Code
and the regulations promulgated thereunder and that such transfer of the
Residual Certificate will not be disregarded for federal income tax purposes.
"U.S. Person" means a citizen or resident of the United States, a corporation or
partnership (unless, in the case of a partnership, Treasury regulations are
adopted that provide otherwise) created or organized in or under the laws of the
United States, any state thereof or the District of Columbia, including an
entity treated as a corporation or partnership for federal income tax purposes,
an estate whose income is subject to United States federal income tax regardless
of its source, or a trust if a court within the United States is able to
exercise primary supervision over the administration of such trust, and one or
more such U.S. Persons have the authority to control all substantial decisions
of such trust (or, to the extent provided in applicable Treasury regulations,
certain trusts in existence on August 20, 1996 which are eligible to elect to be
treated as U.S. Persons).

            11. That the Purchaser agrees to such amendments of the Pooling and
Servicing Agreement as may be required to further effectuate the restrictions on
transfer of the Residual Certificate to such a "disqualified organization," an
agent thereof, an ERISA Prohibited Holder or a person that does not satisfy the
requirements of paragraph 4, paragraph 5 and paragraph 10 hereof.

            12. That the Purchaser consents to the designation of the Master
Servicer as its agent to act as "tax matters person" of the REMIC pursuant to
Section 8.13 of the Pooling and Servicing Agreement, and if such designation is
not permitted by the Code and applicable law, to act as tax matters person if
requested to do so.

<PAGE>

            IN WITNESS WHEREOF, the Purchaser has caused this instrument to be
executed on its behalf, pursuant to authority of its Board of Directors, by its
[Title of Officer] this ___ day of , 20__.

                                       [NAME OF PURCHASER]

                                       By:____________________________________
                                          [Name of Officer]
                                          [Title of Officer]

            Personally appeared before me the above-named [Name of Officer],
known or proved to me to be the same person who executed the foregoing
instrument and to be the [Title of Officer], of the Purchaser, and acknowledged
to me that he [she] executed the same as his [her] free act and deed and the
free act and deed of the Purchaser.

            Subscribed and sworn before me this __ day of __________, 20__.

Notary Public

COUNTY OF____________________

STATE OF_____________________

My commission expires the __ day of __________, 20__.

<PAGE>

                                  ATTACHMENT A

                                       to

 AFFIDAVIT PURSUANT TO SECTION 860E(e)(4) OF THE INTERNAL REVENUE CODE OF 1986,
                     AS AMENDED, AND FOR NON-ERISA INVESTORS

Check the appropriate box:

|_|   The consideration paid to the Purchaser to acquire the Residual
      Certificate equals or exceeds the excess of (a) the present value of the
      anticipated tax liabilities over (b) the present value of the anticipated
      savings associated with holding such Certificate, in each case calculated
      in accordance with U.S. Treasury Regulations Sections 1.860E-1(c)(7) and
      (8), computing present values using a discount rate equal to the
      short-term Federal rate prescribed by Section 1274(d) of the Code and the
      compounding period used by the Purchaser.

                                       OR
                                       --

|_|   The transfer of the Residual Certificate complies with U.S. Treasury
      Regulations Sections 1.860E-1(c)(5) and (6) and, accordingly:

      (i)   the Purchaser is an "eligible corporation," as defined in U.S.
            Treasury Regulations Section 1.860E-1(c)(6)(i), as to which income
            from Residual Certificate will only be taxed in the United States;

      (ii)  at the time of the transfer, and at the close of the Purchaser's two
            fiscal years preceding the year of the transfer, the Purchaser had
            gross assets for financial reporting purposes (excluding any
            obligation of a person related to the Purchaser within the meaning
            of U.S. Treasury Regulations Section 1.860E-1(c)(6)(ii)) in excess
            of $100 million and net assets in excess of $10 million;

      (iii) the Purchaser will transfer the Residual Certificate only to another
            "eligible corporation," as defined in U.S. Treasury Regulations
            Section 1.860E-1(c)(6)(i), in a transaction that satisfies the
            requirements of Sections 1.860E-1(c)(4)(i), (ii) and (iii) and
            Section 1.860E-1(c)(5) of the U.S. Treasury Regulations;

      (iv)  the Purchaser has determined the consideration paid to it to acquire
            the Residual Certificate based on reasonable market assumptions
            (including, but not limited to, borrowing and investment rates,
            prepayment and loss assumptions, expense and reinvestment
            assumptions, tax rates and other factors specific to the Purchaser)
            that it has determined in good faith; and

      (v)   in the event of any transfer of the Residual Certificate by the
            Purchaser, the Purchaser will require its transferee to complete a
            representation in the form of this Attachment A as a condition of
            the transferee's purchase of the Residual Certificate.

<PAGE>

                                    EXHIBIT I

                 Letter from Transferor of Residual Certificate

                                     [Date]

Wells Fargo Bank, N.A.
9062 Old Annapolis Road
Columbia, Maryland 21045-1951
Attn: Corporate Trust Services- WFMBS 2007-17

      Re:   Wells Fargo Asset Securities Corporation,
            Series 2007-17, Class A-R
            -------------------------

Ladies and Gentlemen:

            [Transferor] has reviewed the attached affidavit of [Transferee],
and has no actual knowledge that such affidavit is not true and has no reason to
know that the information contained in paragraph 4 thereof is not true.

                                       Very truly yours,

                                       [Transferor]

                                       ______________________

<PAGE>

                                    EXHIBIT J

                    WELLS FARGO ASSET SECURITIES CORPORATION

                       MORTGAGE PASS-THROUGH CERTIFICATES
                                 SERIES 2007-17
                       CLASS [B-4][B-5][B-6] CERTIFICATES

                               TRANSFEREE'S LETTER
                               -------------------

                                                      _________________ __, ____

Wells Fargo Bank, N.A.
9062 Old Annapolis Road
Columbia, Maryland 21045-1951
Attn: Corporate Trust Services WFMBS 2007-17

Wells Fargo Asset Securities Corporation
5325 Spectrum Drive
Frederick, Maryland 21703

            The undersigned (the "Purchaser") proposes to purchase Wells Fargo
Asset Securities Corporation Mortgage Pass-Through Certificates, Series 2007-17,
Class [B-4][B-5][B-6] Certificates (the "Class [B-4][B-5][B-6] Certificates") in
the principal amount of $___________. In doing so, the Purchaser hereby
acknowledges and agrees as follows:

            Section 1. Definitions. Each capitalized term used herein and not
otherwise defined herein shall have the meaning ascribed to it in the Pooling
and Servicing Agreement, dated as of December 20, 2007 (the "Pooling and
Servicing Agreement") among Wells Fargo Asset Securities Corporation, as
depositor (the "Depositor"), Wells Fargo Bank, N.A., as master servicer (the
"Master Servicer") and HSBC Bank USA, National Association, as trustee (the
"Trustee"), of Wells Fargo Asset Securities Corporation Mortgage Pass-Through
Certificates, Series 2007-17.

            Section 2. Representations and Warranties of the Purchaser. In
connection with the proposed transfer, the Purchaser represents and warrants to
the Depositor, the Master Servicer and the Trustee that:

            (a) The Purchaser is duly organized, validly existing and in good
standing under the laws of the jurisdiction in which the Purchaser is organized,
is authorized to invest in the Class [B-4][B-5][B-6] Certificates, and to enter
into this Agreement, and duly executed and delivered this Agreement. (b) The
Purchaser is acquiring the Class [B-4][B-5][B-6] Certificates for its own
account as principal and not with a view to the distribution thereof, in whole
or in part.

            (c) The Purchaser is a "Qualified Institutional Buyer" within the
meaning of Rule 144A of the Act.

            (d) The Purchaser confirms that (a) it has received and reviewed a
copy of the Private Placement Memorandum dated __________ __, 20__, relating to
the Class [B-4][B-5][B-6] Certificates and reviewed, to the extent it deemed
appropriate, the documents attached thereto or incorporated by reference
therein, (b) it has had the opportunity to ask questions of, and receive answers
from the Depositor concerning the Class [B-4][B-5][B-6] Certificates and all
matters relating thereto, and obtain any additional information (including
documents) relevant to its decision to purchase the Class [B-4][B-5][B-6]
Certificates that the Depositor possesses or can possess without unreasonable
effort or expense and (c) it has undertaken its own independent analysis of the
investment in the Class [B-4][B-5][B-6] Certificates. The Purchaser will not use
or disclose any information it receives in connection with its purchase of the
Class [B-4][B-5][B-6] Certificates other than in connection with a subsequent
sale of Class [B-4][B-5][B-6] Certificates.

            (e) With respect to the Class [B-4][B-5][B-6] Certificates, either
(i) the Purchaser is not an employee benefit plan or other retirement
arrangement subject to Title I of the Employee Retirement Income Security Act of
1974, as amended, ("ERISA"), or Section 4975 of the Internal Revenue Code of
1986, as amended (the "Code"), or a governmental plan, as defined in Section
3(32) of ERISA subject to any federal, state or local law ("Similar Law") which
is, to a material extent, similar to the foregoing provisions of ERISA or the
Code (collectively, a "Plan"), an agent acting on behalf of a Plan, or a person
utilizing the assets of a Plan or (ii) if the Purchaser is an insurance company,
(A) the source of funds used to purchase the Class [B-4][B-5][B-6] Certificate
is an "insurance company general account" (as such term is defined in Section
V(e) of Prohibited Transaction Class Exemption 95-60 ("PTE 95-60"), 60 Fed. Reg.
35925 (July 12, 1995), (B) there is no Plan with respect to which the amount of
such general account's reserves and liabilities for the contract(s) held by or
on behalf of such Plan and all other Plans maintained by the same employer (or
affiliate thereof as defined in Section V(a)(1) of PTE 95-60) or by the same
employee organization exceeds 10% of the total of all reserves and liabilities
of such general account (as such amounts are determined under Section I(a) of
PTE 95-60) at the date of acquisition and (C) the purchase and holding of such
Class [B-4][B-5][B-6] Certificates are covered by Sections I and III of PTE
95-60 or (iii) the Purchaser has provided (a) a "Benefit Plan Opinion"
satisfactory to the Depositor and the Master Servicer of the Trust Estate and
(b) such other opinions of counsel, officers' certificates and agreements as the
Depositor or the Master Servicer may have required. A Benefit Plan Opinion is an
opinion of counsel to the effect that the proposed transfer will not constitute
or result in a non-exempt prohibited transaction within the meaning of ERISA,
Section 4975 of the Code or Similar Law and will not subject the Depositor or
the Master Servicer to any obligation in addition to those undertaken in the
Pooling and Servicing Agreement (including any liability for civil penalties or
excise taxes imposed pursuant to ERISA, Section 4975 of the Code or Similar
Law).

            (f) If the Purchaser is a depository institution subject to the
jurisdiction of the Office of the Comptroller of the Currency ("OCC"), the Board
of Governors of the Federal Reserve System ("FRB"), the Federal Deposit
Insurance Corporation ("FDIC"), the Office of Thrift Supervision ("OTS") or the
National Credit Union Administration ("NCUA"), the Purchaser has reviewed the
"Supervisory Policy Statement on Securities Activities" dated January 28, 1992
of the Federal Financial Institutions Examination Council and the April 15, 1994
Interim Revision thereto as adopted by the OCC, FRB, FDIC, OTS and NCUA (with
modifications as applicable), as appropriate, other applicable investment
authority, rules, supervisory policies and guidelines of these agencies and, to
the extent appropriate, state banking authorities and has concluded that its
purchase of the Class [B-4][B-5][B-6] Certificates is in compliance therewith.

            Section 3. Transfer of Class [B-4][B-5][B-6] Certificates.

            (a) The Purchaser understands that the Class [B-4][B-5][B-6]
Certificates have not been registered under the Securities Act of 1933 (the
"Act") or any state securities laws and that no transfer may be made unless the
Class [B-4][B-5][B-6] Certificates are registered under the Act and applicable
state law or unless an exemption from registration is available. The Purchaser
further understands that neither the Depositor nor the Master Servicer is under
any obligation to register the Class [B-4][B-5][B-6] Certificates or make an
exemption available. Any such Certificateholder desiring to effect such transfer
shall, and does hereby agree to, indemnify the Trustee, the Master Servicer, any
Paying Agent and the Depositor against any liability that may result if the
transfer is not so exempt or is not made in accordance with such federal and
state laws.

            (b) No transfer of a Class [B-4][B-5][B-6] Certificate shall be made
unless the transferee provides the Depositor and the Master Servicer with a
Transferee's Letter, substantially in the form of this Agreement.

            (c) The Purchaser acknowledges that its Class [B-4][B-5][B-6]
Certificates bear a legend setting forth the applicable restrictions on
transfer.

<PAGE>

            IN WITNESS WHEREOF, the undersigned has caused this Agreement to be
validly executed by its duly authorized representative as of the day and the
year first above written.

                                       [PURCHASER]

                                       By: ______________________________

                                       Its: _____________________________

<PAGE>

                                    EXHIBIT K

                           LIST OF RECORDATION STATES

                                     Florida

                                    Maryland

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                                    EXHIBIT L

                              SERVICING AGREEMENTS

                      Wells Fargo Bank Servicing Agreement

     [Included as Exhibit 10.1 to the Current Report on Form 8-K pursuant to

              which this Pooling and Servicing Agreement is filed]

                   Colonial Savings, F.A. Servicing Agreement

                             [Intentionally Omitted]

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                                    EXHIBIT M

                      [FORM OF SPECIAL SERVICING AGREEMENT]

                 SPECIAL SERVICING AND COLLATERAL FUND AGREEMENT
                 -----------------------------------------------

      This SPECIAL SERVICING AND COLLATERAL FUND AGREEMENT (the "Agreement") is
made and entered into as of [ ], between Wells Fargo Bank, N.A. (the "Company"
or the "Master Servicer") and [ ] (the "Purchaser").

                              PRELIMINARY STATEMENT

      The Purchaser is the holder of the entire interest in Wells Fargo Asset
Securities Corporation Mortgage Pass-Through Certificates, Series [ ], Class [ ]
(the "Class B Certificates"), which are the Lowest Priority Certificates (as
defined below) outstanding with respect to such Series. The Class B Certificates
were issued pursuant to a Pooling and Servicing Agreement dated as of [ ] among
Wells Fargo Asset Securities Corporation, as depositor (the "Depositor"), Wells
Fargo Bank, N.A., as Master Servicer, and HSBC Bank USA, National Association,
as Trustee.

      In connection with the ownership by the Purchaser of the Lowest Priority
Certificates, the Purchaser and the Company have agreed that (i) the Purchaser,
for so long as it owns 100% of the Lowest Priority Certificates, will have the
unilateral right to control foreclosure decisions with respect to delinquent
mortgage loans and (ii) the Company will provide to the Purchaser certain
information with respect to the Mortgage Loans;

      The parties hereto have agreed that the Company will cause, to the extent
that the Company as Master Servicer is granted such authority in the related
Servicing Agreements, the related servicers (each a related "Servicer"), which
service the Mortgage Loans which comprise the Trust Estate related to the above
referenced series under the related servicing agreements (each a related
"Servicing Agreement"), to engage in certain special servicing procedures
relating to foreclosures for the benefit of the Purchaser, and that the
Purchaser will deposit funds in a collateral fund to cover any losses
attributable to such procedures as well as all advances and costs in connection
therewith, as set forth herein.

      In consideration of the mutual agreements herein contained, the receipt
and sufficiency of which are hereby acknowledged, the Company and the Purchaser
agree that the following provisions shall become effective and shall be binding
on and enforceable by the Company and the Purchaser:

<PAGE>

                                    ARTICLE I

                                   DEFINITIONS

            Section 1.02. Defined Terms.

      Whenever used in this Agreement, the following words and phrases, unless
the context otherwise requires, shall have the following meanings:

      Business Day: Any day other than (i) a Saturday or a Sunday or (ii) a day
on which banking institutions in the State of New York are required or
authorized by law or executive order to be closed.

      Collateral Fund: The fund established and maintained pursuant to Section
3.01 hereof.

      Collateral Fund Permitted Investments: Either (i) obligations of, or
obligations fully guaranteed as to principal and interest by, the United States,
or any agency or instrumentality thereof, provided such obligations are backed
by the full faith and credit of the United States, (ii) a money market fund
rated in the highest rating category by a nationally recognized rating agency
selected by the Company, (iii) cash, (iv) mortgage pass-through certificates
issued or guaranteed by Government National Mortgage Association, FNMA or FHLMC,
(v) commercial paper (including both non-interest-bearing discount obligations
and interest-bearing obligations payable on demand or on a specified date), the
issuer of which may be an affiliate of the Company, having at the time of such
investment a rating of at least F-1 by Fitch Ratings ("Fitch") or at least P-1
by Moody's Investors Service Inc. ("Moody's") or (vi) demand and time deposits
in, certificates of deposit of, any depository institution or trust company
(which may be an affiliate of the Company) incorporated under the laws of the
United States of America or any state thereof and subject to supervision and
examination by federal and/or state banking authorities, so long as at the time
of such investment either (x) the long-term debt obligations of such depository
institution or trust company have a rating of at least AA by Fitch or Aa2 by
Moody's, (y) the certificate of deposit or other unsecured short-term debt
obligations of such depository institution or trust company have a rating of at
least F-1 by Fitch or P-1 by Moody's or (z) the depository institution or trust
company is one that is acceptable to either Fitch or Moody's and, for each of
the preceding clauses (i), (iv), (v) and (vi), the maturity thereof shall be not
later than the earlier to occur of (A) 30 days from the date of the related
investment and (B) the next succeeding Distribution Date as defined in the
related Pooling and Servicing Agreement.

      Commencement of Foreclosure: The first official action required under
local law in order to commence foreclosure proceedings or to schedule a
trustee's sale under a deed of trust, including (i) in the case of a mortgage,
any filing or service of process necessary to commence an action to foreclose,
or (ii) in the case of a deed of trust, posting, the publishing, filing or
delivery of a notice of sale, but not including in either case (x) any notice of
default, notice of intent to foreclose or sell or any other action prerequisite
to the actions specified in (i) or (ii) above, (y) the acceptance of a
deed-in-lieu of foreclosure (whether in connection with a sale of the related
property or otherwise) or (z) initiation and completion of a short pay-off.

      Current Appraisal: With respect to any Mortgage Loan as to which the
Purchaser has made an Election to Delay Foreclosure, an appraisal of the related
Mortgaged Property obtained by the Purchaser at its own expense from an
independent appraiser (which shall not be an affiliate of the Purchaser)
acceptable to the Company as nearly contemporaneously as practicable to the time
of the Purchaser's election, prepared based on the Company's customary
requirements for such appraisals.

      Election to Delay Foreclosure: Any election by the Purchaser to delay the
Commencement of Foreclosure, made in accordance with Section 2.02(b).

      Election to Foreclose: Any election by the Purchaser to proceed with the
Commencement of Foreclosure, made in accordance with Section 2.03(a).

      Lowest Priority Certificates: The most subordinate class of certificates
issued under the Pooling and Servicing Agreement that is outstanding from time
to time. If the Lowest Priority Certificates are reduced to zero as a result of
losses or otherwise, and if the Purchaser at that time owns 100% of the most
subordinate class of certificates issued under the Pooling and Servicing
Agreement then remaining outstanding, then such most subordinate class remaining
outstanding shall thereafter be deemed to be the Lowest Priority Certificates
for all purposes of this Agreement.

      Monthly Advances: Principal and interest advances and servicing advances
including costs and expenses of foreclosure.

      Required Collateral Fund Balance: As of any date of determination, an
amount equal to the aggregate of all amounts previously required to be deposited
in the Collateral Fund pursuant to Section 2.02(d) (after adjustment for all
withdrawals and deposits pursuant to Section 2.02(e)) and Section 2.03(b) (after
adjustment for all withdrawals and deposits pursuant to Section 2.03(c)) and
Section 3.02 to be reduced by all withdrawals therefrom pursuant to Section
2.02(g) and Section 2.03(d).

            Section 1.03. Definitions Incorporated by Reference.

      All capitalized terms not otherwise defined in this Agreement shall have
the meanings assigned in the Pooling and Servicing Agreement.

                                   ARTICLE II

                          SPECIAL SERVICING PROCEDURES

            Section 2.01. Reports and Notices.

            (a) In connection with the performance of its duties under the
Pooling and Servicing Agreement relating to the realization upon defaulted
Mortgage Loans, the Company as Master Servicer shall provide to the Purchaser
the following notices and reports:

      Within five Business Days after each Distribution Date (or included in or
      with the monthly statements to Certificateholders pursuant to the Pooling
      and Servicing Agreement), the Company shall provide to the Purchaser a
      report identifying all loans delinquent 30 days or more (including all
      loans in foreclosure, bankruptcy or "real estate owned" status) (each, a
      "Delinquency Report"). The Delinquency Report shall use the same
      methodology and calculations employed in the Company's standard servicing
      reports, indicating the number of Mortgage Loans that are (i) thirty days
      delinquent, (ii) sixty days delinquent, (iii) ninety days or more
      delinquent, (iv) in foreclosure, (v) in bankruptcy or (vi) real estate
      owned, and indicating for each such Mortgage Loan the loan number, the
      property address and the outstanding principal balance.

            (b) If requested by the Purchaser, the Company shall cause the
Servicer (to the extent that the Company as Master Servicer is granted such
authority in the related Servicing Agreement) to make its servicing personnel
available (during their normal business hours) to respond to reasonable
inquiries, by phone or in writing by facsimile, electronic, or overnight mail
transmission, by the Purchaser in connection with any Mortgage Loan (i)
identified in a report under Section 2.01 (a) (ii), (a) (iii), (a) (iv), (a) (v)
or (a) (vi); provided, that (1) the related Servicer shall only be required to
provide information that is readily accessible to its servicing personnel and
(2) the related Servicer shall respond within five Business Days orally or in
writing by facsimile transmission.

            (c) In addition to the foregoing, the Company shall cause the
Servicer (to the extent that the Company as Master Servicer is granted such
authority in the related Servicing Agreement) to provide to the Company (for
prompt transmission to the Purchaser) such information as the Purchaser may
reasonably request provided, however, that such information is consistent with
normal reporting practices, concerning each Mortgage Loan that is at least
ninety days delinquent and each Mortgage Loan which has become real estate
owned, through the final liquidation thereof; provided, that the related
Servicer shall only be required to provide information that is readily
accessible to its servicing personnel; provided, however, that the Purchaser
will reimburse the Company and the related Servicer for any out of pocket
expenses.

            Section 2.02. Purchaser's Election to Delay Foreclosure Proceedings.

            (a) The Purchaser shall be deemed to direct the Company to direct
(to the extent that the Company as Master Servicer is granted such authority in
the related Servicing Agreement) the related Servicer that in the event that the
Company does not receive written notice of the Purchaser's election pursuant to
subsection (b) below within 48 hours (exclusive of any intervening non-Business
Days) of transmission of the Delinquency Report provided by the Company under
Section 2.01 (a) (subject to extension as set forth in Section 2.02(b), the
related Servicer may proceed with the Commencement of Foreclosure in respect of
each Mortgage Loan reported under Section 2.01 (a)(ii) or 2.01 (a)(iii) in
accordance with its normal foreclosure policies without further notice to the
Purchaser. Any foreclosure that has been initiated may be discontinued (i)
without notice to the Purchaser if the Mortgage Loan has been brought current or
if a refinancing or prepayment occurs with respect to the Mortgage Loan
(including by means of a short payoff approved by the related Servicer) or (ii)
if the related Servicer has reached the terms of a forbearance agreement with
the borrower.

            (b) In connection with any Mortgage Loan reported in a Delinquency
Report under Section 2.01(a)(ii) or 2.01 (a)(iii), the Purchaser may elect to
instruct the Company to cause, to the extent that the Company as Master Servicer
is granted such authority in the related Servicing Agreement, the related
Servicer to delay the Commencement of Foreclosure until such time as the
Purchaser determines that the related Servicer may proceed with the Commencement
of Foreclosure. Such election must be evidenced by written notice received
within 48 hours (exclusive of any intervening non-Business Days) of transmission
of the Delinquency Report provided by the Company under Section 2.01(a). Such 48
hour period shall be extended for no longer than an additional four Business
Days after the receipt of the information if the Purchaser requests additional
information related to such foreclosure; provided, however, that the Purchaser
will have at least one Business Day to respond to any requested additional
information. Any such additional information shall be provided only to the
extent it is obtainable by the related Servicer from existing reports,
certificates or statements or is otherwise readily accessible to its servicing
personnel. The Purchaser agrees that it has no right to deal with the mortgagor
during such period. However, if such servicing activities include acceptance of
a deed-in-lieu of foreclosure or short payoff, the Purchaser will be notified
and given two Business Days to respond.

            (c) With respect to any Mortgage Loan as to which the Purchaser has
made an Election to Delay Foreclosure, the Purchaser shall obtain a Current
Appraisal as soon as practicable, but in no event more than 15 Business Days
thereafter, and shall provide the Company with a copy of such Current Appraisal.

            (d) Within two Business Days of making any Election to Delay
Foreclosure, the Purchaser shall remit by wire transfer to the Company, for
deposit in the Collateral Fund, an amount, as calculated by the Company, equal
to the sum of (i) 125% of the greater of the unpaid principal balance of the
Mortgage Loan and the value shown in the Current Appraisal referred to in
subsection (c) above (or, if such Current Appraisal has not yet been obtained,
the Company's estimate thereof, in which case the required deposit under this
subsection shall be adjusted upon obtaining such Current Appraisal), and (ii)
three months' interest on the Mortgage Loan at the applicable Mortgage Interest
Rate. If any Election to Delay Foreclosure extends for a period in excess of
three months (such excess period being referred to herein as the "Excess
Period"), within two Business Days the Purchaser shall remit by wire transfer in
advance to the Company for deposit in the Collateral Fund the amount of each
additional month's interest, as calculated by the Company, equal to interest on
the Mortgage Loan at the applicable Mortgage Interest Rate for the Excess
Period. The terms of this Agreement will no longer apply to the servicing of any
Mortgage Loan upon the failure of the Purchaser to deposit any of the above
amounts relating to the Mortgage Loan within two Business Days of the Election
to Delay Foreclosure or within two Business Days of the commencement of the
Excess Period subject to Section 3.01.

            (e) With respect to any Mortgage Loan as to which the Purchaser has
made an Election to Delay Foreclosure, the Company may withdraw from the
Collateral Fund from time to time amounts necessary to reimburse the related
Servicer for all related Monthly Advances and Liquidation Expenses thereafter
made by such Servicer in accordance with the Pooling and Servicing Agreement and
the related Servicing Agreement. To the extent that the amount of any such
Liquidation Expenses is determined by the Company based on estimated costs, and
the actual costs are subsequently determined to be higher, the Company may
withdraw the additional amount from the Collateral Fund. In the event that the
Mortgage Loan is brought current by the mortgagor and the foreclosure action is
discontinued, the amounts so withdrawn from the Collateral Fund shall be
redeposited if and to the extent that reimbursement therefor from amounts paid
by the mortgagor is not prohibited pursuant to the Pooling and Servicing
Agreement or the related Servicing Agreement, applicable law or the related
mortgage note. Except as provided in the preceding sentence, amounts withdrawn
from the Collateral Fund to cover Monthly Advances and Liquidation Expenses
shall not be redeposited therein or otherwise reimbursed to the Purchaser. If
and when any such Mortgage Loan is brought current by the mortgagor, all amounts
remaining in the Collateral Fund in respect of such Mortgage Loan (after
adjustment for all permitted withdrawals and deposits pursuant to this
subsection) shall be released to the Purchaser.

            (f) With respect to any Mortgage Loan as to which the Purchaser has
made an Election to Delay Foreclosure, the related Servicer shall continue to
service the Mortgage Loan in accordance with its customary procedures (other
than the delay in Commencement of Foreclosure as provided herein). If and when
the Purchaser shall notify the Company that it believes that it is appropriate
to do so, the related Servicer may proceed with the Commencement of Foreclosure.
In any event, if the Mortgage Loan is not brought current by the mortgagor by
the time the loan becomes 6 months delinquent, the Purchaser's election shall no
longer be effective and at the Purchaser's option, either (i) the Purchaser
shall purchase the Mortgage Loan from the related Trust Estate at a purchase
price equal to the sum of (x) accrued and unpaid interest on the Mortgage Loan
at the applicable Mortgage Interest Rate through the last day of the month of
repurchase, (y) 100% of the unpaid principal balance of the Mortgage Loan as of
such purchase date and (z) any additional amount needed to reimburse any
unreimbursed related Periodic Advance or other servicing advances made in
respect of such Mortgage Loan, to be paid by (A) applying any balance in the
Collateral Fund to such purchase price, and (B) to the extent of any deficiency,
by wire transfer of immediately available funds from the Purchaser to the
Company for deposit in the related Certificate Account; or (ii) the related
Servicer shall proceed with the Commencement of Foreclosure. In the event that
the Purchaser purchases any such Mortgage Loan, the Servicer shall continue to
service the Mortgage Loan for the Purchaser pursuant to the applicable Servicing
Agreement.

            (g) Upon the occurrence of a liquidation with respect to any
Mortgage Loan as to which the Purchaser made an Election to Delay Foreclosure
and as to which the related Servicer proceeded with the Commencement of
Foreclosure in accordance with subsection (f) above, the Company shall calculate
the amount, if any, by which the value shown on the Current Appraisal obtained
under subsection (c) exceeds the actual sales price obtained for the related
Mortgaged Property (net of Liquidation Expenses and accrued interest related to
the extended foreclosure period), and the Company shall withdraw the amount of
such excess from the Collateral Fund, shall remit the same to the Trust Estate
and in its capacity as Master Servicer shall apply such amount as additional
Liquidation Proceeds pursuant to the Pooling and Servicing Agreement. After
making such withdrawal, all amounts remaining in the Collateral Fund in respect
of such Mortgage Loan (after adjustment for all permitted withdrawals and
deposits pursuant to this Agreement) shall be released to the Purchaser.

            Section 2.03. Purchaser's Election to Commence Foreclosure
Proceedings.

            (a) In connection with any Mortgage Loan identified in a Delinquency
Report under Section 2.01(a)(ii), the Purchaser, for so long as the Purchaser
owns 100% of the Lowest Priority Certificates, may elect to instruct the Company
to cause, to the extent that the Company as Master Servicer is granted such
authority in the related Servicing Agreement, the related Servicer to proceed
with the Commencement of Foreclosure as soon as practicable. Such election must
be evidenced by written notice received by the Company by 5:00 p.m., New York
City time, on the third Business Day following the delivery of such Delinquency
Report.

            (b) Within two Business Days of making any Election to Foreclose,
the Purchaser shall remit to the Company, for deposit in the Collateral Fund, an
amount, as calculated by the Company, equal to 125% of the current unpaid
principal balance of the Mortgage Loan and three months interest on the Mortgage
Loan at the applicable Mortgage Interest Rate. If and when any such Mortgage
Loan is brought current by the mortgagor, all amounts in the Collateral Fund in
respect of such Mortgage Loan (after adjustment for all permitted withdrawals
and deposits pursuant to this Agreement) shall be released to the Purchaser if
and to the extent that reimbursement therefor from amounts paid by the mortgagor
is not prohibited pursuant to the Pooling and Servicing Agreement or the related
Servicing Agreement, applicable law or the related mortgage note. The terms of
this Agreement will no longer apply to the servicing of any Mortgage Loan upon
the failure of the Purchaser to deposit the above amounts relating to the
Mortgage Loan within two Business Days of the Election to Foreclose subject to
Section 3.01.

            (c) With respect to any Mortgage Loan as to which the Purchaser has
made an Election to Foreclose, the related Servicer shall continue to service
the Mortgage Loan in accordance with its customary procedures (other than
Commencement of Foreclosure as provided herein). In connection therewith, the
Company shall have the same rights to make withdrawals for Monthly Advances and
Liquidations Expenses from the Collateral Fund as are provided under Section
2.02(e), and the Company shall make reimbursements thereto to the limited extent
provided under such subsection in accordance with its customary procedures. The
Company shall not be required to cause, to the extent that the Company as Master
Servicer is granted such authority in the related Servicing Agreement, the
related Servicer to proceed with the Commencement of Foreclosure if (i) the same
is stayed as a result of the mortgagor's bankruptcy or is otherwise barred by
applicable law, or to the extent that all legal conditions precedent thereto
have not yet been complied with, or (ii) the Company believes there is a breach
of representations or warranties by the Company, a Servicer, or the Depositor,
which may result in a repurchase or substitution of such Mortgage Loan, or (iii)
the Company or related Servicer reasonably believes the Mortgaged Property may
be contaminated with or affected by hazardous wastes or hazardous substances
(and, without limiting the related Servicer's right not to proceed with the
Commencement of Foreclosure, the Company supplies the Purchaser with information
supporting such belief). Any foreclosure that has been initiated may be
discontinued (x) without notice to the Purchaser if the Mortgage Loan has been
brought current or if a refinancing or prepayment occurs with respect to the
Mortgage Loan (including by means of a short payoff) or (y) if the related
Servicer has reached the terms of a forbearance agreement.

            (d) Upon the occurrence of a liquidation with respect to any
Mortgage Loan as to which the Purchaser made an Election to Foreclose and as to
which the related Servicer proceeded with the Commencement of Foreclosure in
accordance with subsection (c) above, the Company shall calculate the amount, if
any, by which the unpaid principal balance of the Mortgage Loan at the time of
liquidation (plus all unreimbursed interest and servicing advances and
Liquidation Expenses in connection therewith other than those paid from the
Collateral Fund) exceeds the actual sales price obtained for the related
Mortgaged Property, and the Company shall withdraw the amount of such excess
from the Collateral Fund, shall remit the same to the Trust Estate and in its
capacity as Master Servicer shall apply such amount as additional Liquidation
Proceeds pursuant to the Pooling and Servicing Agreement. After making such
withdrawal, all amounts remaining in the Collateral Fund (after adjustment for
all withdrawals and deposits pursuant to subsection (c) in respect of such
Mortgage Loan shall be released to the Purchaser.

            Section 2.04. Termination.

            (a) With respect to all Mortgage Loans included in the Trust Estate,
the Purchaser's right to make any Election to Delay Foreclosure or any Election
to Foreclose and the Company's obligations under Section 2.01 shall terminate
(i) at such time as the Principal Balance of the Class B Certificates has been
reduced to zero, (ii) if the greater of (x) 43% (or such lower or higher
percentage that represents the related Servicer's actual historical loss
experience with respect to the Mortgage Loans in the related pool as determined
by the Company) of the aggregate principal balance of all Mortgage Loans that
are in foreclosure or are more than 90 days delinquent on a contractual basis
and REO properties or (y) the aggregate amount that the Company estimates
through the normal servicing practices of the related Servicer will be required
to be withdrawn from the Collateral Fund with respect to Mortgage Loans as to
which the Purchaser has made an Election to Delay Foreclosure or an Election to
Foreclosure, exceeds (z) the then-current principal balance of the Class B
Certificates, (iii) upon any transfer by the Purchaser of any interest (other
than the minority interest therein, but only if the transferee provides written
acknowledgment to the Company of the Purchaser's right hereunder and that such
transferee will have no rights hereunder) in the Class B Certificates (whether
or not such transfer is registered under the Pooling and Servicing Agreement),
including any such transfer in connection with a termination of the Trust Estate
or (iv) upon any breach of the terms of this Agreement by the Purchaser.

            (b) Except as set forth in 2.04(a), this Agreement and the
respective rights, obligations and responsibilities of the Purchaser and the
Company hereunder shall terminate upon the later to occur of (i) the final
liquidation of the last Mortgage Loan as to which the Purchaser made any
Election to Delay Foreclosure or any Election to Foreclose and the withdrawal of
all remaining amounts in the Collateral Fund as provided herein and (ii) ten
Business Days' notice. The Purchaser's right to make an election pursuant to
Section 2.02 or Section 2.03 hereof with respect to a particular Mortgage Loan
shall terminate if the Purchaser fails to make any deposit required pursuant to
Section 2.02(d) or 2.03(b) or if the Purchaser fails to make any other deposit
to the Collateral Fund pursuant to this Agreement.

                                   ARTICLE III

                       COLLATERAL FUND; SECURITY INTEREST

            Section 3.01. Collateral Fund.

      Upon receipt from the Purchaser of the initial amount required to be
deposited in the Collateral Fund pursuant to Article II, the Company shall
establish and maintain with [ ] as a segregated account on its books and records
an account (the "Collateral Fund"), entitled "Wells Fargo Bank, N.A., as Master
Servicer, for the benefit of registered holders of Wells Fargo Asset Securities
Corporation Mortgage Pass-Through Certificates, Series [ ]." Amounts held in the
Collateral Fund shall continue to be the property of the Purchaser, subject to
the first priority security interest granted hereunder for the benefit of the
Certificateholders, until withdrawn from the Collateral Fund pursuant to Section
2.02 or 2.03 hereof. The Collateral Fund shall be an "outside reserve fund"
within the meaning of the REMIC Provisions, beneficially owned by the Purchaser
for federal income tax purposes. All income, gain, deduction or loss with
respect to the Collateral Fund shall be that of the Purchaser. All distributions
from the Trust Fund to the Collateral Fund shall be treated as distributed to
the Purchaser as the beneficial owner thereof.

      Upon the termination of this Agreement and the liquidation of all Mortgage
Loans as to which the Purchaser has made any Election to Delay Foreclosure or
any Election to Foreclose pursuant to Section 2.04 hereof, the Company shall
distribute or cause to be distributed to the Purchaser all amounts remaining in
the Collateral Fund (after adjustment for all deposits and permitted withdrawals
pursuant to this Agreement) together with any investment earnings thereon. In
the event the Purchaser has made any Election to Delay Foreclosure or any
Election to Foreclose, prior to any distribution to the Purchaser of all amounts
remaining in the Collateral Fund, funds in the Collateral Fund shall be applied
consistent with the terms of this Agreement.

            Section 3.02. Collateral Fund Permitted Investments.

      The Company shall, at the written direction of the Purchaser, invest the
funds in the Collateral Fund in Collateral Fund Permitted Investments. Such
direction shall not be changed more frequently than quarterly. In the absence of
any direction, the Company shall select such investments in accordance with the
definition of Collateral Fund Permitted Investments in its discretion. All
income and gain realized from any investment as well as any interest earned on
deposits in the Collateral Fund (net of any losses on such investments) and any
payments of principal made in respect of any Collateral Fund Permitted
Investment shall be deposited in the Collateral Fund upon receipt. All costs and
realized losses associated with the purchase and sale of Collateral Fund
Permitted Investments shall be borne by the Purchaser and the amount of net
realized losses shall be deposited by the Purchaser in the Collateral Fund
promptly upon realization. The Company shall periodically (but not more
frequently than monthly) distribute to the Purchaser upon request an amount of
cash, to the extent cash is available therefore in the Collateral Fund, equal to
the amount by which the balance of the Collateral Fund, after giving effect to
all other distributions to be made from the Collateral Fund on such date,
exceeds the Required Collateral Fund Balance. Any amounts so distributed shall
be released from the lien and security interest of this Agreement.

            Section 3.03. Grant of Security Interest.

      The Purchaser hereby grants to the Company for the benefit of the
Certificateholders under the Pooling and Servicing Agreement a security interest
in and lien on all of the Purchaser's right, title and interest, whether now
owned or hereafter acquired, in and to: (1) the Collateral Fund, (2) all amounts
deposited in the Collateral Fund and Collateral Fund Permitted Investments in
which such amounts are invested (and the distributions and proceeds of such
investments) and (3) all cash and non-cash proceeds of any of the foregoing,
including proceeds of the voluntary conversion thereof (all of the foregoing
collectively, the "Collateral").

      The Purchaser acknowledges the lien on and the security interest in the
Collateral for the benefit of the Certificateholders. The Purchaser shall take
all actions requested by the Company as may be reasonably necessary to perfect
the security interest created under this Agreement in the Collateral and cause
it to be prior to all other security interests and liens, including the
execution and delivery to the Company for filing of appropriate financing
statements in accordance with applicable law. The Company shall file appropriate
continuation statements, or appoint an agent on its behalf to file such
statements, in accordance with applicable law.

            Section 3.04. Collateral Shortfalls.

      In the event that amounts on deposit in the Collateral Fund at any time
are insufficient to cover any withdrawals therefrom that the Company is then
entitled to make hereunder, the Purchaser shall be obligated to pay such amounts
to the Company immediately upon demand. Such obligation shall constitute a
general corporate obligation of the Purchaser. The failure to pay such amounts
within two Business Days of such demand (except for amounts to cover interest on
a Mortgage Loan pursuant to Sections 2.02(d) and 2.03 (b)), shall cause an
immediate termination of the Purchaser's right to make any Election to Delay
Foreclosure or Election to Foreclose and the Company's obligations under this
Agreement with respect to all Mortgage Loans to which such insufficiencies
relate, without the necessity of any further notice or demand on the part of the
Company.

                                   ARTICLE IV

            Section 4.01. Assessment of Servicing Compliance; Registered Public
Accounting Firm Attestation Reports; Exchange Act Reporting.

            (a) The Purchaser shall furnish, or cause to be furnished in the
case of clause (iii), to the Master Servicer, no later than March 5 of each year
or if such day is not a Business Day, the next Business Day (with a 10 calendar
day cure period, but in no event later than March 15), commencing in March 20 ,
the following:

            (i) a report (in form and substance reasonably satisfactory to the
      Master Servicer and the Depositor) regarding the Purchaser's assessment of
      compliance with the Servicing Criteria applicable to it during the
      immediately preceding calendar year, as required under Rules 13a-18 and
      15d-18 of the Exchange Act and Item 1122 of Regulation AB. Such report
      shall be addressed to the Master Servicer and signed by an authorized
      officer of the Purchaser, and shall address, at a minimum, each of the
      Servicing Criteria applicable to the Purchaser;

            (ii) a report of a registered public accounting firm reasonably
      acceptable to the Master Servicer and the Depositor that attests to, and
      reports on, the assessment of compliance made by the Purchaser and
      delivered pursuant to the preceding paragraph. Such attestation shall be
      in accordance with Rules 1-02(a)(3) and 2-02(g) of Regulation S-X under
      the Securities Act and the Exchange Act. If requested by the Master
      Servicer or the Depositor, such report shall contain or be accompanied by
      a consent of such accounting firm to inclusion or incorporation of such
      report in the Depositor's Registration Statement on Form S-3 relating to
      the Certificates and the Trust's Form 10-K; and

            (iii) an assessment of compliance and accountants' attestation as
      described in paragraphs (i) and (ii) of this Section 4.01(a) with respect
      to each Subcontractor determined by the Purchaser pursuant to Section 4.02
      to be "participating in the servicing function" within the meaning of Item
      1122 of Regulation AB.

            An assessment of compliance provided by a Subcontractor pursuant to
Section 4.01(a)(iii) need not address any elements of the Servicing Criteria
applicable to it other than those specified by the Purchaser pursuant to Section
4.02.

            No later than 30 days following the end of each fiscal year for the
Trust for which a Form 10-K is required to be filed, the Purchaser shall forward
to the Master Servicer the name of each Subcontractor engaged by it and what
Servicing Criteria will be addressed in the report on assessment of compliance
prepared by such Subcontractor. When the Purchaser submits its assessment to the
Master Servicer, it will also at such time include the assessment (and
attestation pursuant to Section 4.01(a)(ii) hereof) of each Subcontractor
engaged by it.

            (b) Within five (5) calendar days after a Distribution Date, the
Purchaser shall provide to the Master Servicer, to the extent known, in
EDGAR-compatible format, or in such other form as otherwise agreed upon by the
Master Servicer and the Purchaser, the form and substance of any Additional Form
10-D Disclosure applicable to the Purchaser, as indicated in the table in
Exhibit S to the Pooling and Servicing Agreement. The Purchaser acknowledges
that the performance by the Master Servicer of its duties under Section 3.12(a)
of the Pooling and Servicing Agreement relating to the timely preparation and
filing of Form 10-D is contingent upon the Purchaser strictly observing all
applicable deadlines in the performance of its duties under this Section
4.01(b).

            (c) No later than March 5 (with a 10 calendar day cure period, but
in no event later than March 15) of each year that the Trust is subject to the
Exchange Act reporting requirements, commencing in March 20 , the Purchaser
shall provide to the Master Servicer, to the extent known, in EDGAR-compatible
format, or in such other form as otherwise agreed upon by the Master Servicer
and the Purchaser, the form and substance of any Additional Form 10-K Disclosure
applicable to the Purchaser, as indicated in the table in Exhibit T to the
Pooling and Servicing Agreement. The Purchaser acknowledges that the performance
by the Master Servicer of its duties under Section 3.12(b) of the Pooling and
Servicing Agreement relating to the timely preparation and filing of Form 10-K
is contingent upon the Purchaser strictly observing all applicable deadlines in
the performance of its duties under this Section 4.01(c).

            (d) For so long as the Trust is subject to the Exchange Act
reporting requirements, no later than the end of business on the second Business
Day after the occurrence of a Reportable Event applicable to the Purchaser, the
Purchaser shall provide to the Master Servicer, to the extent known, in
EDGAR-compatible format, or in such other form as otherwise agreed upon by the
Master Servicer and the Purchaser, the form and substance of any Form 8-K
Disclosure Information applicable to the Purchaser, as indicated in the table in
Exhibit U to the Pooling and Servicing Agreement. The Purchaser acknowledges
that the performance by the Master Servicer of its duties under Section 3.12(c)
of the Pooling and Servicing Agreement relating to the timely preparation and
filing of Form 8-K is contingent upon the Purchaser strictly observing all
applicable deadlines in the performance of its duties under this Section
4.01(d).

            (e) The Purchaser shall provide such information regarding itself as
the Master Servicer or the Depositor request for the purpose of complying with
Item 1108 of Regulation AB, including at a minimum, the information set forth in
Exhibit A.

            (f) The Purchaser shall indemnify the Master Servicer, each
affiliate of the Master Servicer, the Trust, each broker dealer acting as
underwriter or initial purchaser of the Certificates, each Person who controls
any of such parties and the Depositor (within the meaning of Section 15 of the
Securities Act and Section 20 of the Exchange Act); and the respective present
and former directors, officers, employees and agents of each of the foregoing
and of the Depositor (each such entity, an "Indemnified Party"), and shall hold
each of them harmless from and against any losses, damages, penalties, fines,
forfeitures, legal fees and expenses and related costs, judgments, and any other
costs, fees and expenses that any of them may sustain arising out of or based
upon:

                  (i) (A) any untrue statement of a material fact contained or
            alleged to be contained in any information, report, certification,
            accountants' letter or other material provided in written or
            electronic form under this Section 4.01 or Section 4.02 hereof by or
            on behalf of the Purchaser, or provided under Sections 4.01 or 4.02
            by or on behalf of any Subcontractor (collectively, the "Purchaser
            Information"), or (B) the omission or alleged omission to state in
            the Purchaser Information a material fact required to be stated in
            the Purchaser Information or necessary in order to make the
            statements therein, in the light of the circumstances under which
            they were made, not misleading; provided, by way of clarification,
            that clause (B) of this paragraph shall be construed solely by
            reference to the Purchaser Information and not to any other
            information communicated in connection with a sale or purchase of
            securities, without regard to whether the Purchaser Information or
            any portion thereof is presented together with or separately from
            such other information; or

                  (ii) any failure by the Purchaser or any Subcontractor engaged
            by the Purchaser to deliver any information, report, certification,
            accountants' letter or other material when and as required under
            Sections 4.01 or 4.02, including any failure by the Purchaser to
            identify pursuant to Section 4.02 any Subcontractor "participating
            in the servicing function" within the meaning of Item 1122 of
            Regulation AB.

      In the case of any failure of performance described in clause (ii) of this
Section, the Purchaser shall promptly reimburse the Master Servicer and the
Depositor, as applicable, for all costs reasonably incurred by each such party
in order to obtain the information, report, certification, accountants' letter
or other material not delivered as required by the Purchaser or any
Subcontractor. If the indemnification provided for herein is unavailable to hold
harmless any Indemnified Party, then the Purchaser agrees that it shall
contribute to the amount paid or payable by such Indemnified Party as a result
of the losses, claims, damages or liabilities of such Indemnified Party in such
proportion as is appropriate to reflect the relative fault of such Indemnified
Party on the one hand and the Purchaser on the other in connection with a breach
of the Purchaser's obligations under this Section 4.1 or the Purchaser's
negligence, bad faith or willful misconduct in connection therewith.

            (g) Notwithstanding anything contained in this Section 4.01 to the
contrary, the provisions of this Section 4.01 shall not apply to the Purchaser
with respect to any calendar year unless the Purchaser exercises its rights set
forth under Sections 2.02 or 2.03 of this Agreement in such calendar year.

            Section 4.02. Engagement of Affiliates or Third-Parties.

            The Purchaser shall not hire any Subservicer without the consent of
the Master Servicer and the Depositor. The Purchaser shall not hire or otherwise
utilize the services of any Subcontractor to fulfill any of the obligations of
the Purchaser as servicer under this Agreement unless the Purchaser complies
with the provisions of this Section.

            It shall not be necessary for the Purchaser to seek the consent of
the Master Servicer or the Depositor to the utilization of any Subcontractor.
The Purchaser shall promptly upon request provide to the Master Servicer (or any
designee of Master Servicer) a written description (in form and substance
satisfactory to the Master Servicer and the Depositor) of the role and function
of each Subcontractor utilized by the Purchaser, specifying (i) the identity of
each such Subcontractor, (ii) which (if any) of such Subcontractors are
"participating in the servicing function" within the meaning of Item 1122 of
Regulation AB, and (iii) which elements of the Servicing Criteria will be
addressed in assessments of compliance provided by each Subcontractor identified
pursuant to clause (ii) of this paragraph.

            As a condition to the utilization of any Subcontractor determined to
be "participating in the servicing function" within the meaning of Item 1122 of
Regulation AB, the Purchaser shall cause any such Subcontractor used by the
Purchaser, for the benefit of the Master Servicer and the Depositor to comply
with the provisions of Section 4.01 of this Agreement to the same extent as if
such Subcontractor were the Purchaser. The Purchaser shall be responsible for
obtaining from each Subcontractor and delivering to the Master Servicer any
assessment of compliance and attestation required to be delivered by such
Subcontractor under Section 4.01, in each case as and when required to be
delivered.

            Section 4.03. Notification of Merger.

            The Purchaser and such successor or surviving Person shall notify
the Depositor, the Master Servicer and the Trustee of any such merger,
conversion or consolidation at least two Business Days prior to the effective
date thereof and shall provide the Depositor and the Master Servicer with all
information required by the Depositor to comply with its reporting obligations
not later than the effective date of such merger, conversion or consolidation
(unless giving prior notice would be prohibited by applicable law or by a
confidentiality agreement, in which case notice shall be given by 12 noon
eastern time one Business Day after such merger or consolidation).

            Section 4.04. Compliance with Article IV.

            If (a) the Purchaser fails to comply with its obligations to deliver
any assessment of servicing compliance or registered public accounting firm
attestation reports required pursuant to this Article IV or (b) any
Subcontractor engaged by the Purchaser fails to comply with its obligations to
deliver any assessment of servicing compliance or registered public accounting
firm attestation reports, the Master Servicer, may, after consultation with the
Depositor, terminate this Agreement pursuant to Section 2.04(a)(iv).

                                    ARTICLE V

                            MISCELLANEOUS PROVISIONS

            Section 5.01. Amendment.

      This Agreement may be amended from time to time by the Company and the
Purchaser by written agreement signed by the Company and the Purchaser, subject
to the acknowledgement of the Rating Agencies as contemplated in Section 3.08 of
the Pooling and Servicing Agreement with respect to such amendment.

            Section 5.02. Counterparts.

      This Agreement may be executed simultaneously in any number of
counterparts, each of which counterparts shall be deemed to be an original, and
such counterparts shall constitute but one and the same instrument.

            Section 5.03. Governing Law.

      This Agreement shall be construed in accordance with the laws of the State
of New York and the obligations, rights and remedies of the parties hereunder
shall be determined in accordance with such laws.

            Section 5.04. Notices.

      All demands, notices and direction hereunder shall be in writing or by
telecopy and shall be deemed effective upon receipt to:

      (a)   in the case of the Company,
            Wells Fargo Bank, N.A. 9062 Old
            Annapolis Road
            Columbia, MD 21045

            Attention: Vice President, Master Servicing
            Phone: 410-884-2000
            Fax: 410-715-1573

      (b) in the case of the Purchaser,

            Section 5.05. Severability of Provisions.

      If any one or more of the covenants, agreements, provisions or terms of
this Agreement shall be for any reason whatsoever, including regulatory, held
invalid, then such covenants, agreements, provisions or terms of this Agreement
and shall in no way affect the validity or enforceability of the other
provisions of this Agreement.

            Section 5.06. Successors and Assigns.

The provisions of this Agreement shall be binding upon and inure to the benefit
of the respective successors and assigns of the parties hereto, and all such
provisions shall inure to the benefit of the Certificateholders; provided,
however, that the rights under this Agreement cannot be assigned by the
Purchaser without the consent of the Company.

            Section 5.07. Article and Section Headings.

      The article and section headings herein are for convenience of reference
only and shall not limit or otherwise affect the meaning hereof.

            Section 5.08. Confidentiality.

      The Purchaser agrees that all information supplied by or on behalf of the
Company pursuant to Sections 2.01 or 2.02, including individual account
information, is the property of the Company and the Purchaser agrees to hold
such information confidential and not to disclose such information.

      Each party hereto agrees that neither it, nor any officer, director,
employee, affiliate or independent contractor acting at such party's direction
will disclose the terms of Section 5.09 of this Agreement to any person or
entity other than such party's legal counsel except pursuant to a final,
non-appealable order of court, the pendency of such order the other party will
have received notice of at least five business days prior to the date thereof,
or pursuant to the other party's prior express written consent.

            Section 5.09. Indemnification.

      The Purchaser agrees to indemnify and hold harmless the Company, the
Depositor, and each Servicer and each person who controls the Company, the
Depositor, or a Servicer and each of their respective officers, directors,
affiliates and agents acting at the Company's, the Depositor's, or a Servicer's
direction (the "Indemnified Parties") against any and all losses, claims,
damages or liabilities to which they may be subject, insofar as such losses,
claims, damages or liabilities (or actions in respect thereof) arise out of, or
are based upon, actions taken by, or actions not taken by, the Company, the
Depositor, or a Servicer, or on their behalf, in accordance with the provisions
of this Agreement and (i) which actions conflict with the Company's, the
Depositor's, or a Servicer's obligations under the Pooling and Servicing
Agreement or the related Servicing Agreement, or (ii) give rise to securities
law liability under federal or state securities laws with respect to the
Certificates. The Purchaser hereby agrees to reimburse the Indemnified Parties
for the reasonable legal or other expenses incurred by them in connection with
investigating or defending any such loss, claim, damage, liability or action.
The indemnification obligations of the Purchaser hereunder shall survive the
termination or expiration of this Agreement.

            Section 5.10 Regulation AB Compliance; Intent of Parties;
Reasonableness.

            The parties hereto acknowledge that interpretations of the
requirements of Regulation AB may change over time, whether due to interpretive
guidance provided by the Commission or its staff, consensus among participants
in the asset-backed securities markets, advice of counsel, or otherwise, and
agree to comply with requests made by the Depositor or the Master Servicer in
good faith for delivery of information under these provisions on the basis of
evolving interpretations of Regulation AB. In connection with the Trust, the
parties hereto shall cooperate fully with the Master Servicer and the Depositor
to deliver to the Master Servicer and/or the Depositor (including its assignees
or designees), any and all statements, reports, certifications, records and any
other information available to such party and reasonably necessary in the good
faith determination of the Depositor or the Master Servicer to permit the
Depositor or the Master Servicer to comply with the provisions of Regulation AB,
together with such disclosures reasonably believed by the Depositor or the
Master Servicer to be necessary in order to effect such compliance.

<PAGE>

      IN WITNESS WHEREOF, the Company and the Purchaser have caused their names
to be signed hereto by their respective officers thereunto duly authorized, all
as of the day and year first above written.

                                    WELLS FARGO BANK, N.A.

                                    By:
                                    ___________________________________
                                    Name:
                                    Title:

                                    [NAME OF PURCHASER]

                                    By:
                                    ___________________________________
                                    Name:
                                    Title:

<PAGE>

                                                                       EXHIBIT A
                                                                       ---------

                              PURCHASER INFORMATION

      (A) the Purchaser's form of organization;

      (B) a description of how long the Purchaser has been servicing residential
mortgage loans; a general discussion of the Purchaser's experience in servicing
assets of any type as well as a more detailed discussion of the Purchaser's
experience in, and procedures for, the servicing function it will perform under
the Agreement; information regarding the size, composition and growth of the
Purchaser's portfolio of residential mortgage loans of a type similar to the
Mortgage Loans and information on factors related to the Purchaser that may be
material, in the good faith judgment of the Master Servicer or the Depositor, to
any analysis of the servicing of the Mortgage Loans or the related asset-backed
securities, as applicable, including, without limitation:

            (1) whether any prior securitizations of mortgage loans of a type
      similar to the Mortgage Loans involving the Purchaser have defaulted or
      experienced an early amortization or other performance triggering event
      because of servicing during the three-year period immediately preceding
      the date of engagement of the Purchaser;

            (2) the extent of outsourcing the Purchaser utilizes;

            (3) whether there has been previous disclosure of material
      noncompliance with the applicable servicing criteria with respect to
      securitizations of residential mortgage loans involving the Purchaser as a
      servicer during the three-year period immediately preceding the date of
      engagement of the Purchaser;

            (4) whether the Purchaser has been terminated as servicer in a
      residential mortgage loan securitization, either due to a servicing
      default or to application of a servicing performance test or trigger; and

            (5) such other information as the Master Servicer or the Depositor
      may reasonably request for the purpose of compliance with Item 1108(b)(2)
      of Regulation AB;

      (C) a description of any material changes during the three-year period
immediately preceding the date of engagement of the Purchaser to the Purchaser's
policies or procedures with respect to the servicing function it will perform
under the Agreement for mortgage loans of a type similar to the Mortgage Loans;

      (D) information regarding the Purchaser's financial condition, to the
extent that there is a material risk that an adverse financial event or
circumstance involving the Purchaser could have a material adverse effect on the
performance by the Purchaser of its servicing obligations under the Agreement;

      (E) information regarding advances made by the Purchaser on the Mortgage
Loans and the Purchaser's overall servicing portfolio of residential mortgage
loans for the three-year period immediately preceding the date of engagement of
the Purchaser, which may be limited to a statement by an authorized officer of
the Purchaser to the effect that the Purchaser has made all advances required to
be made on residential mortgage loans serviced by it during such period, or, if
such statement would not be accurate, information regarding the percentage and
type of advances not made as required, and the reasons for such failure to
advance;

      (F) a description of the Purchaser's processes and procedures designed to
address any special or unique factors involved in servicing loans of a similar
type as the Mortgage Loans;

      (G) a description of the Purchaser's processes for handling delinquencies,
losses, bankruptcies and recoveries, such as through liquidation of mortgaged
properties, sale of defaulted mortgage loans or workouts; and

      (H) information as to how the Purchaser defines or determines
delinquencies and charge-offs, including the effect of any grace period,
re-aging, restructuring, partial payments considered current or other practices
with respect to delinquency and loss experience.

<PAGE>

                                    EXHIBIT N

                 FORM OF INITIAL CERTIFICATION OF THE CUSTODIAN

                                December 20, 2007

Wells Fargo Asset Securities Corporation
5325 Spectrum Drive
Frederick, Maryland  21703

Wells Fargo Bank, N.A.
9062 Old Annapolis Road
Columbia, Maryland 21045-1951
Attn: Corporate Trust Services WFMBS 2007-17

HSBC Bank USA, National Association
452 Fifth Avenue
New York, New York 10018
Attention: Alexander Pabon

      Re:   The Pooling and Servicing Agreement, dated December 20, 2007, among
            Wells Fargo Asset Securities Corporation, as Depositor, Wells Fargo
            Bank, N.A., as Master Servicer, and HSBC Bank USA, National
            Association, as Trustee, relating to the Wells Fargo Asset
            Securities Corporation; Mortgage Pass-Through Certificates, Series
            2007-17.
            -------

Ladies and Gentlemen:

      In accordance with the provisions of Section 2.02 of the above-referenced
Pooling and Servicing Agreement (the "Pooling and Servicing Agreement"), the
undersigned, as Custodian on behalf of the Trustee, hereby certifies that,
except as specified in any list of exceptions attached hereto, it has received
the original Mortgage Note relating to each of the Mortgage Loans listed on the
Mortgage Loan Schedule.

      The Custodian has made no independent examination of any documents
contained in each Mortgage File beyond the review specifically required in the
Pooling and Servicing Agreement in connection with this initial certification.
The Custodian makes no representations as to: (i) the validity, legality,
sufficiency, enforceability, recordability or genuineness of any of the
documents contained in each Mortgage File or any of the Mortgage Loans
identified in the Mortgage Loan Schedule or (ii) the collectibility,
insurability, effectiveness or suitability of any such Mortgage Loan.

<PAGE>

      Capitalized terms used but not defined herein shall have the meanings
ascribed to such terms in the Pooling and Servicing Agreement.

                                    WELLS FARGO BANK, N.A.,
                                      as Custodian on behalf of the Trustee

                                    By:_________________________________________
                                    Name:_______________________________________
                                    Title:______________________________________

<PAGE>

                                    EXHIBIT O

                  FORM OF FINAL CERTIFICATION OF THE CUSTODIAN

                              [__________ __, ____]

Wells Fargo Asset Securities Corporation
5325 Spectrum Drive
Frederick, Maryland  21703

Wells Fargo Bank, N.A.
9062 Old Annapolis Road
Columbia, Maryland 21045-1951
Attn: Corporate Trust Services WFMBS 2007-17

HSBC Bank USA, National Association
452 Fifth Avenue
New York, New York 10018
Attention: Alexander Pabon

      Re:   The Pooling and Servicing Agreement, dated December 20, 2007, among
            Wells Fargo Asset Securities Corporation, as Depositor, Wells Fargo
            Bank, N.A., as Master Servicer, and HSBC Bank USA, National
            Association, as Trustee, relating to the Wells Fargo Asset
            Securities Corporation; Mortgage Pass-Through Certificates, Series
            2007-17.
            -------

Ladies and Gentlemen:

      In accordance with the provisions of Section 2.02 of the above-referenced
Pooling and Servicing Agreement (the "Pooling and Servicing Agreement"), the
undersigned, as Custodian on behalf of the Trustee, hereby certifies that, as to
each Mortgage Loan listed in the Mortgage Loan Schedule, except as may be
specified in any list of exceptions attached hereto, such Mortgage File contains
all of the items required to be delivered pursuant to Section 2.01 of the
Pooling and Servicing Agreement.

      The Custodian has made no independent examination of any documents
contained in each Mortgage File beyond the review specifically required in the
Pooling and Servicing Agreement in connection with this final certification. The
Custodian makes no representations as to: (i) the validity, legality,
sufficiency, enforceability, recordability or genuineness of any of the
documents contained in each Mortgage File or any of the Mortgage Loans
identified in the Mortgage Loan Schedule or (ii) the collectibility,
insurability, effectiveness or suitability of any such Mortgage Loan.

<PAGE>

      Capitalized terms used but not defined herein shall have the meanings
ascribed to such terms in the Pooling and Servicing Agreement.

                                    WELLS FARGO BANK, N.A.,
                                      as Custodian on behalf of the Trustee

                                    By:_________________________________________
                                    Name:_______________________________________
                                    Title:______________________________________

<PAGE>

                                    EXHIBIT P

                      FORM OF SARBANES-OXLEY CERTIFICATION

                    Wells Fargo Asset Securities Corporation
                       Mortgage Pass-Through Certificates,
                                 Series 2007-17

            I, [________], certify that:

      1. I have reviewed this report on Form 10-K and all reports on Form 10-D
required to be filed in respect of the period covered by this report on Form
10-K of the Wells Fargo Asset Securities Corporation, Mortgage Pass-Through
Certificates, Series 2007-17 Trust (the "Exchange Act Periodic Reports");

      2. Based on my knowledge, the Exchange Act Periodic Reports, taken as a
whole, do not contain any untrue statement of a material fact or omit to state a
material fact necessary to make the statements made, in light of the
circumstances under which such statements were made, not misleading with respect
to the period covered by this report;

      3. Based on my knowledge, all of the distribution, servicing and other
information required to be provided under Form 10-D for the period covered by
this report is included in the Exchange Act Periodic Reports;

      4. I am responsible for reviewing the activities performed by the Master
Servicer and based upon my knowledge and the compliance review conducted in
preparing the servicer compliance statement required in this report under Item
1123 of Regulation AB, and except as disclosed in the Exchange Act Periodic
Reports, the Master Servicer has fulfilled its obligations under the pooling and
servicing agreement, dated December 20, 2007, among Wells Fargo Asset Securities
Corporation, as depositor, Wells Fargo Bank, N.A., as master servicer, and HSBC
Bank USA, National Association, as trustee, in all material respects; and

      5. All of the reports on assessment of compliance with the servicing
criteria for asset-backed securities and their related attestation reports on
assessment of compliance with servicing criteria for asset-backed securities
required to be included in this report in accordance with Item 1122 of
Regulation AB and Exchange Act Rules 13a-18 and 15d-18 have been included as an
exhibit to this report, except as otherwise disclosed in this report. Any
material instances of noncompliance described in such reports have been
disclosed in this report on Form 10-K.

      [The following is included only for a transaction where there are
Servicers other than Wells Fargo Bank: In giving the certifications above, I
have reasonably relied on information provided to me by the following
unaffiliated parties: [Name of Servicers other than Wells Fargo Bank], as
Servicer.]

Date: [_____]

                                       By:______________________________________
                                          Name:
                                          Title:
                                          (senior officer in charge of the
                                          servicing function of the master
                                          servicer)

<PAGE>

                                    EXHIBIT Q

                                    Reserved

<PAGE>

                                    EXHIBIT R

         Servicing Criteria to be Addressed in Assessment of Compliance

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------------------
                                            SERVICING CRITERIA                               APPLICABLE SERVICING CRITERIA
------------------------------------------------------------------------------------------------------------------------------
                                                                                        Master
     Reference                                  Criteria                               Servicer  Trustee  Servicers  Custodian
------------------------------------------------------------------------------------------------------------------------------
                                    General Servicing Considerations
------------------------------------------------------------------------------------------------------------------------------
<S>               <C>                                                                  <C>       <C>      <C>        <C>
                  Policies and procedures are instituted to monitor any performance        X      X(1)        X
                  or other triggers and events of default in accordance with the
1122(d)(1)(i)     transaction agreements.
------------------------------------------------------------------------------------------------------------------------------
                  If any material servicing activities are outsourced to third             X                  X
                  parties, policies and procedures are instituted to monitor the
                  third party's performance and compliance with such servicing
1122(d)(1)(ii)    activities.
------------------------------------------------------------------------------------------------------------------------------
                  Any requirements in the transaction agreements to maintain a
1122(d)(1)(iii)   back-up servicer for the mortgage loans are maintained.
------------------------------------------------------------------------------------------------------------------------------
                  A fidelity bond and errors and omissions policy is in effect on the      X        X         X          X
                  party participating in the servicing function throughout the
                  reporting period in the amount of coverage required by and
                  otherwise in accordance with the terms of the transaction
1122(d)(1)(iv)    agreements.
------------------------------------------------------------------------------------------------------------------------------
                                   Cash Collection and Administration
------------------------------------------------------------------------------------------------------------------------------
                  Payments on mortgage loans are deposited into the appropriate            X                  X
                  custodial bank accounts and related bank clearing accounts no more
                  than two business days following receipt, or such other number of
1122(d)(2)(i)     days specified in the transaction agreements.
------------------------------------------------------------------------------------------------------------------------------
                  Disbursements made via wire transfer on behalf of an obligor or to       X                  X
1122(d)(2)(ii)    an investor are made only by authorized personnel.
------------------------------------------------------------------------------------------------------------------------------
                  Advances of funds or guarantees regarding collections, cash flows        X      X (2)       X
                  or distributions, and any interest or other fees charged for such
                  advances, are made, reviewed and approved as specified in the
1122(d)(2)(iii)   transaction agreements.
------------------------------------------------------------------------------------------------------------------------------
                  The related accounts for the transaction, such as cash reserve           X                  X
                  accounts or accounts established as a form of
                  overcollateralization, are separately maintained (e.g., with
                  respect to commingling of cash) as set forth in the transaction
1122(d)(2)(iv)    agreements.
------------------------------------------------------------------------------------------------------------------------------
                  Each custodial account is maintained at a federally insured              X                  X
                  depository institution as set forth in the transaction agreements.
                  For purposes of this criterion, "federally insured depository
                  institution" with respect to a foreign financial institution means
                  a foreign financial institution that meets the requirements of Rule
1122(d)(2)(v)     13k-1(b)(1) of the Securities Exchange Act.
------------------------------------------------------------------------------------------------------------------------------
                  Unissued checks are safeguarded so as to prevent unauthorized            X                  X
1122(d)(2)(vi)    access.
------------------------------------------------------------------------------------------------------------------------------
                  Reconciliations are prepared on a monthly basis for all                  X                  X
                  asset-backed securities related bank accounts, including custodial
                  accounts and related bank clearing accounts. These reconciliations
                  are (A) mathematically accurate; (B) prepared within 30 calendar
                  days after the bank statement cutoff date, or such other number of
                  days specified in the transaction agreements; (C) reviewed and
                  approved by someone other than the person who prepared the
                  reconciliation; and (D) contain explanations for reconciling items.
                  These reconciling items are resolved within 90 calendar days of
                  their original identification, or such other number of days
1122(d)(2)(vii)   specified in the transaction agreements.
------------------------------------------------------------------------------------------------------------------------------
                                   Investor Remittances and Reporting
------------------------------------------------------------------------------------------------------------------------------
                  Reports to investors, including those to be filed with the               X                  X
                  Commission, are maintained in accordance with the transaction
                  agreements and applicable Commission requirements. Specifically,
                  such reports (A) are prepared in accordance with timeframes and
                  other terms set forth in the transaction agreements; (B) provide
                  information calculated in accordance with the terms specified in
                  the transaction agreements; (C) are filed with the Commission as
                  required by its rules and regulations; and (D) agree with
                  investors' or the trustee's records as to the total unpaid
                  principal balance and number of mortgage loans serviced by the
1122(d)(3)(i)     Servicer.
------------------------------------------------------------------------------------------------------------------------------
                  Amounts due to investors are allocated and remitted in accordance        X                  X
                  with timeframes, distribution priority and other terms set forth in
1122(d)(3)(ii)    the transaction agreements.
------------------------------------------------------------------------------------------------------------------------------
                  Disbursements made to an investor are posted within two business         X                  X
                  days to the Servicer's investor records, or such other number of
1122(d)(3)(iii)   days specified in the transaction agreements.
------------------------------------------------------------------------------------------------------------------------------
                  Amounts remitted to investors per the investor reports agree with        X                  X
                  cancelled checks, or other form of payment, or custodial bank
1122(d)(3)(iv)    statements.
------------------------------------------------------------------------------------------------------------------------------
                                       Pool Asset Administration
------------------------------------------------------------------------------------------------------------------------------
                  Collateral or security on mortgage loans is maintained as required       X                  X          X
1122(d)(4)(i)     by the transaction agreements or related mortgage loan documents.
------------------------------------------------------------------------------------------------------------------------------
                  Mortgage loan and related documents are safeguarded as required by                          X          X
1122(d)(4)(ii)    the transaction agreements
------------------------------------------------------------------------------------------------------------------------------
                  Any additions, removals or substitutions to the asset pool are           X        X         X
                  made, reviewed and approved in accordance with any conditions or
1122(d)(4)(iii)   requirements in the transaction agreements.
------------------------------------------------------------------------------------------------------------------------------
                  Payments on mortgage loans, including any payoffs, made in                                  X
                  accordance with the related mortgage loan documents are posted to
                  the Servicer's obligor records maintained no more than two business
                  days after receipt, or such other number of days specified in the
                  transaction agreements, and allocated to principal, interest or
                  other items (e.g., escrow) in accordance with the related mortgage
1122(d)(4)(iv)    loan documents.
------------------------------------------------------------------------------------------------------------------------------
                  The Servicer's records regarding the mortgage loans agree with the                          X
                  Servicer's records with respect to an obligor's unpaid principal
1122(d)(4)(v)     balance.
------------------------------------------------------------------------------------------------------------------------------
                  Changes with respect to the terms or status of an obligor's              X                  X
                  mortgage loans (e.g., loan modifications or re-agings) are made,
                  reviewed and approved by authorized personnel in accordance with
1122(d)(4)(vi)    the transaction agreements and related pool asset documents.
------------------------------------------------------------------------------------------------------------------------------
                  Loss mitigation or recovery actions (e.g., forbearance plans,            X                  X
                  modifications and deeds in lieu of foreclosure, foreclosures and
                  repossessions, as applicable) are initiated, conducted and
                  concluded in accordance with the timeframes or other requirements
1122(d)(4)(vii)   established by the transaction agreements.
------------------------------------------------------------------------------------------------------------------------------
                  Records documenting collection efforts are maintained during the                            X
                  period a mortgage loan is delinquent in accordance with the
                  transaction agreements. Such records are maintained on at least a
                  monthly basis, or such other period specified in the transaction
                  agreements, and describe the entity's activities in monitoring
                  delinquent mortgage loans including, for example, phone calls,
                  letters and payment rescheduling plans in cases where delinquency
1122(d)(4)(viii)  is deemed temporary (e.g., illness or unemployment).
------------------------------------------------------------------------------------------------------------------------------
                  Adjustments to interest rates or rates of return for mortgage loans                         X
                  with variable rates are computed based on the related mortgage loan
1122(d)(4)(ix)    documents.
------------------------------------------------------------------------------------------------------------------------------
                  Regarding any funds held in trust for an obligor (such as escrow                            X
                  accounts): (A) such funds are analyzed, in accordance with the
                  obligor's mortgage loan documents, on at least an annual basis, or
                  such other period specified in the transaction agreements; (B)
                  interest on such funds is paid, or credited, to obligors in
                  accordance with applicable mortgage loan documents and state laws;
                  and (C) such funds are returned to the obligor within 30 calendar
                  days of full repayment of the related mortgage loans, or such other
1122(d)(4)(x)     number of days specified in the transaction agreements.
------------------------------------------------------------------------------------------------------------------------------
                  Payments made on behalf of an obligor (such as tax or insurance                             X
                  payments) are made on or before the related penalty or expiration
                  dates, as indicated on the appropriate bills or notices for such
                  payments, provided that such support has been received by the
                  servicer at least 30 calendar days prior to these dates, or such
1122(d)(4)(xi)    other number of days specified in the transaction agreements.
------------------------------------------------------------------------------------------------------------------------------
                  Any late payment penalties in connection with any payment to be                             X
                  made on behalf of an obligor are paid from the Servicer's funds and
                  not charged to the obligor, unless the late payment was due to the
1122(d)(4)(xii)   obligor's error or omission.
------------------------------------------------------------------------------------------------------------------------------
                  Disbursements made on behalf of an obligor are posted within two                            X
                  business days to the obligor's records maintained by the Servicer,
                  or such other number of days specified in the transaction
1122(d)(4)(xiii)  agreements.
------------------------------------------------------------------------------------------------------------------------------
                  Delinquencies, charge-offs and uncollectible accounts are                X                  X
                  recognized and recorded in accordance with the transaction
1122(d)(4)(xiv)   agreements.
------------------------------------------------------------------------------------------------------------------------------
                  Any external enhancement or other support, identified in Item          X (3)
                  1114(a)(1) through (3) or Item 1115 of Regulation AB, is maintained
1122(d)(4)(xv)    as set forth in the transaction agreements.
------------------------------------------------------------------------------------------------------------------------------
</TABLE>

[_______________________]

Date: _________________________

By:____________________________
   Name:
   Title:

(1)   This Servicing Criterion applies to the Trustee with respect to Events of
      Default as set forth in the Pooling and Servicing Agreement.
(2)   This Servicing Criterion applies to the Trustee if the Trustee was
      required during the preceding calendar year to make an Advance in
      accordance with Section 8.14 of the Pooling and Servicing Agreement.
(3)   This Servicing Criterion applies to the Master Servicer only for
      transactions that contain any external credit enhancement or other support
      identified in Item 1114(a)(1) through (3) or Item 1115 of Regulation AB.

<PAGE>

                                    EXHIBIT S

                         Additional Form 10-D Disclosure

-------------------------------------------------------------------------------
Item on Form 10-D                           Party Responsible

-------------------------------------------------------------------------------
Item 1: Distribution and Pool               Master Servicer, Depositor
        Performance Information

      Any information required by 1121
      which is NOT included on the
      Distribution Date Statement
-------------------------------------------------------------------------------
Item 2: Legal Proceedings per Item          (i) All parties to the Pooling
        1117 of Reg AB                      and Servicing Agreement, the
                                            Custodian, each Servicer and, if
                                            applicable the Special Servicer (as
                                            to themselves), (ii) the Master
                                            Servicer as to the issuing entity,
                                            (iii) the Depositor as to the
                                            sponsor, any 1110(b) originator, any
                                            1100(d)(1) party
-------------------------------------------------------------------------------
Item 3: Sale of Securities and Use of       Depositor
        Proceeds
-------------------------------------------------------------------------------
Item 4: Defaults Upon Senior Securities     Master Servicer
-------------------------------------------------------------------------------
Item 5: Submission of Matters to a          Master Servicer, Trustee
        Vote of Security Holders
-------------------------------------------------------------------------------
Item 6: Significant Obligors of Pool        Depositor, if applicable
        Assets
-------------------------------------------------------------------------------
Item 7: Significant Enhancement             Depositor, if applicable
        Provider Information
-------------------------------------------------------------------------------
Item 8: Other Information                   Any party responsible for
                                            disclosure items on Form 8-K
-------------------------------------------------------------------------------
Item 9: Exhibits                            Depositor, Master Servicer
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------

<PAGE>

                                    EXHIBIT T

                         Additional Form 10-K Disclosure

-------------------------------------------------------------------------------
Item on Form 10-K                            Party Responsible
-------------------------------------------------------------------------------
Item 1B: Unresolved Staff Comments           Depositor
-------------------------------------------------------------------------------
Item 9B:  Other Information                  Any party responsible for
                                             disclosure items on Form 8-K
-------------------------------------------------------------------------------
Item 15: Exhibits, Financial Statement       Master Servicer
       Schedules                             Depositor
-------------------------------------------------------------------------------
Additional Item:                             (i) All parties to the Pooling
                                             and Servicing Agreement, the
Disclosure per Item 1117 of Reg AB           Custodian, each Servicer and, if
                                             applicable the Special Servicer
                                             (as to themselves), (ii) the
                                             Master Servicer as to the
                                             issuing entity, (iii) the
                                             Depositor as to the sponsor, any
                                             1110(b) originator, any
                                             1100(d)(1) party
-------------------------------------------------------------------------------
Additional Item:                             (i) All parties to the Pooling
Disclosure per Item 1119 of Reg AB           and Servicing Agreement, the
                                             Custodian, each Servicer and, if
                                             applicable the Special Servicer (as
                                             to themselves), (ii) the Master
                                             Servicer as to the issuing entity,
                                             (iii) the Depositor as to the
                                             sponsor, any 1110(b) originator,
                                             any 1100(d)(1) party, any
                                             significant obligor, any credit
                                             enhancement provider or derivative
                                             counterparty

-------------------------------------------------------------------------------
Additional Item:                             Depositor, if applicable
Disclosure per Item 1112(b) of Reg AB
-------------------------------------------------------------------------------
Additional Item:                             Depositor, if applicable
Disclosure per Items 1114(b) and
1115(b) of Reg AB
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------

<PAGE>

                                    EXHIBIT U

                         Form 8-K Disclosure Information

-------------------------------------------------------------------------------
Item on Form 8-K                             Party Responsible
-------------------------------------------------------------------------------
Item 1.01- Entry into a Material             All parties to the Pooling and
           Definitive Agreement              Servicing Agreement, each
                                             Servicer, the Custodian and, if
                                             applicable, the Special Servicer,
                                             as to each agreement to which it is
                                             a party
-------------------------------------------------------------------------------
Item 1.02- Termination of a Material         All parties to the Pooling and
           Definitive Agreement              Servicing Agreement, each
                                             Servicer, the Custodian and, if
                                             applicable, the Special Servicer,
                                             as to each agreement to which it is
                                             a party
-------------------------------------------------------------------------------
Item 1.03- Bankruptcy or Receivership        (i) Depositor, as to itself, the
                                             sponsor, any 1100(d)(1) party,
                                             any significant obligor, any
                                             credit enhancement provider or
                                             derivative counterparty and any
                                             other transaction party, to the
                                             extent known to the Depositor,
                                             (ii) Trustee, as to itself,
                                             (iii) each Servicer as to
                                             itself, (iv) Master Servicer, as
                                             to itself and any other
                                             transaction party, to the extent
                                             known to the Master Servicer
-------------------------------------------------------------------------------
Item 2.04- Triggering Events that            Master Servicer
           Accelerate or Increase a
           Direct Financial Obligation
           or an Obligation under an
           Off-Balance Sheet Arrangement
-------------------------------------------------------------------------------
Item 3.03- Material Modification to          Master Servicer
           Rights of Security Holders
-------------------------------------------------------------------------------
Item 5.03- Amendments of Articles of         Master Servicer
           Incorporation or Bylaws;
           Change of Fiscal Year
-------------------------------------------------------------------------------
Item 6.01- ABS Informational and             Depositor
           Computational Material
-------------------------------------------------------------------------------
Item 6.02- Change of Servicer or             Servicer, Master Servicer
           Master Servicer
-------------------------------------------------------------------------------
Item 6.03- Change in Credit                  Depositor/Master Servicer
           Enhancement or External
           Support
-------------------------------------------------------------------------------
Item 6.04- Failure to Make a Required        Master Servicer
           Distribution
-------------------------------------------------------------------------------
Item 6.05- Securities Act Updating           Depositor
           Disclosure
-------------------------------------------------------------------------------
Item 7.01- Reg FD Disclosure                 Depositor
-------------------------------------------------------------------------------
Item 8.01- Other Events                      Depositor, Master Servicer
-------------------------------------------------------------------------------
Item 9.01                                    Depositor, Master Servicer
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------

<PAGE>

                                    EXHIBIT V

                       Additional Disclosure Notification

**SEND VIA FAX TO 410-715-2380 AND VIA EMAIL TO
CTS.SEC.NOTIFICATIONS@WELLSFARGO.COM AND VIA OVERNIGHT MAIL TO THE ADDRESS
IMMEDIATELY BELOW**

Wells Fargo Bank, N.A., as Master Servicer
9062 Old Annapolis Road
Columbia, Maryland 21045
Attn: Corporate Trust Services- WFMBS 2007-17--SEC REPORT PROCESSING

RE:**[Additional Form [10-D][10-K] Disclosure][Form 8-K Disclosure
Information]** Required

Ladies and Gentlemen:

            In accordance with Section [ ] of the Pooling and Servicing
Agreement, dated as of December 20, 2007, among Wells Fargo Asset Securities
Corporation, as depositor, Wells Fargo Bank, N.A., as master servicer, and HSBC
Bank USA, National Association, as trustee, the undersigned, as [ ], hereby
notifies you that certain events have come to our attention that [will] [may]
need to be disclosed on Form [10-D][10-K][8-K].

Description of [Additional Form [10-D][10-K] Disclosure][Form 8-K Disclosure
Information]:

List of any Attachments hereto to be included in the Additional Form
[10-D][10-K] Disclosure][Form 8-K Disclosure Information]:

            Any inquiries related to this notification should be directed to
[   ], phone number: [   ]; email address: [   ].

                                                [NAME OF PARTY],
                                                as [role]

                                                By: __________________________
                                                    Name:
                                                    Title:

<PAGE>

                                    EXHIBIT W

                               Combination Groups

      Exchangeable REMIC Class             Exchangeable Class
      ------------------------             ------------------

                        Maximum                           Maximum
     Exchangeable       Initial                           Initial
        REMIC          Principal       Exchangeable      Principal
     Combination       Balance(1)      Combination       Balance(1)
     ------------      ----------      ------------      ----------

    Exchangeable
        REMIC                         Exchangeable
    Combination 1                     Combination 1
    -------------     ------------    -------------     ------------
         A-2          $442,329,000         A-1          $460,999,000
         A-3          $18,670,000

            (1) Except as otherwise indicated, Exchangeable REMIC Certificates
and Exchangeable Certificates in any combination may be exchanged only in the
proportion that the Maximum Initial Principal Balances of the indicated Classes
bear to one another as shown above.

<PAGE>

                                    EXHIBIT X

       FORM OF REQUEST FOR EXCHANGE OF EXCHANGEABLE REMIC CERTIFICATES OR
                            EXCHANGEABLE CERTIFICATES

                              [__________ __, ____]

Wells Fargo Bank, N.A.
9062 Old Annapolis Road
Columbia, Maryland 21045
Attn: WFMBS 2007-17

      Re:   Wells Fargo Asset Securities Corporation, Mortgage Pass-Through
            Certificates, Series 2007-17

Ladies and Gentlemen:

            Pursuant to the terms of that certain Pooling and Servicing
Agreement dated as of December 20, 2007 (the "Pooling and Servicing Agreement"),
among Wells Fargo Asset Securities Corporation, as depositor, Wells Fargo Bank,
N.A., as master servicer, and HSBC Bank USA, National Association, as trustee,
we hereby present and surrender the [Exchangeable REMIC Certificates specified
on Schedule I attached hereto (the "Exchangeable REMIC
Certificates")][Exchangeable Certificates specified on Schedule I attached
hereto (the "Exchangeable Certificates")] and transfer, assign, set over and
otherwise convey to the Master Servicer, all of our right, title and interest in
and to the [Exchangeable REMIC Certificates][Exchangeable Certificates],
including all payments of interest thereon received after December 20, 2007, in
exchange for the [Exchangeable Certificates specified on Schedule I attached
hereto (the "Exchangeable Certificates")][Exchangeable REMIC Certificates
specified on Schedule I attached hereto (the "Exchangeable REMIC
Certificates")].

            We agree that upon such exchange the portions of the [Exchangeable
REMIC Certificates][Exchangeable Certificates] designated for exchange shall be
deemed cancelled and replaced by the [Exchangeable Certificates][Exchangeable
REMIC Certificates] issued in exchange therefor. We confirm that we have paid a
fee to the Master Servicer in connection with each such exchange equal to
$5,000.

            Account Details for payments to the Master Servicer:

            Wells Fargo Bank, N.A.
            San Francisco, CA
            ABA #: 121-000-248
            Acct Name: SAS Clearing
            For Further Credit: Account #[       ] - WFMBS 2007-17 Exchange Fee

                                       Sincerely,

                                       By:____________________________________
                                          Name:
                                          Title:

<PAGE>

                                       Acknowledged by:

                                       WELLS FARGO BANK, N.A.,
                                          as Master Servicer

                                       By:____________________________________
                                          Name:
                                          Title:

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