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                                                                  EXHIBIT 10.29





                           PURCHASE AND SALE AGREEMENT




                                  by and among

                              200 CARILLON, L.L.C.,

                                   as Seller,



                       ECHELON INTERNATIONAL CORPORATION,

                                 as a Developer,



                                       and



                      CATALINA MARKETING SALES CORPORATION,

                                    as Buyer



                                October 21, 1999





                       Property: Pinellas County, Florida



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                                TABLE OF CONTENTS


<TABLE>
<S> <C>                                                                       <C>
1.  DEFINITIONS................................................................2

   1.1   DEAL TERMS AND DEADLINES..............................................2
   1.2   STANDARD DEFINED TERMS; DEVELOPMENT AGREEMENT TERMS...................3


2.  DEVELOPMENT, PURCHASE AND SALE.............................................3


3.  SELLER DELIVERABLES........................................................4

      A.    GEOTECHNICAL REPORT................................................4
      B.    ENVIRONMENTAL REPORT...............................................4
      C.    SURVEY.............................................................4
      D.    TITLE COMMITMENT...................................................4


4.  DESIGN AND CONSTRUCTION OF BUILDING AND IMPROVEMENTS.......................4

   4.1   DESIGN-BUILD TURNKEY PROJECT..........................................4

      A.    DEVELOPER ACKNOWLEDGMENT...........................................4

   4.2   PLANS AND SPECIFICATIONS FOR PROJECT..................................5

      A.    LEGAL REQUIREMENTS.................................................5
      B.    CERTIFICATIONS.....................................................5

   4.3   CLAIMS................................................................5

      A.    FORCE MAJEURE......................................................5
      B.    DUTY TO PROCEED/RESOLUTION.........................................5

   4.4   MISCELLANEOUS DESIGN/CONSTRUCTION ISSUES..............................6


5.  PURCHASE PRICE AND PAYMENT.................................................6

   5.1   PURCHASE PRICE........................................................6

      A.    LAND AND BASE BUILDING.............................................7
      B.    TENANT IMPROVEMENTS................................................7
      C.    FINANCING COSTS....................................................7
      D.    BUYER-DIRECTED CHANGE ORDERS.......................................8

   5.2   PAYMENT...............................................................8


6.  CONDITIONS TO CLOSING......................................................9

   6.1   BUYER'S OBLIGATION:  CONDITIONS PRECEDENT.............................9
</TABLE>



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<TABLE>
<S> <C>                                                                       <C>
      A.    ACCURACY OF REPRESENTATIONS........................................9
      B     ENVIRONMENTAL CONDITION............................................9
      C     TITLE AND SURVEY UPDATES...........................................9
         i. MARKED TITLE COMMITMENT............................................9
         ii. UPDATED SURVEY...................................................10
         iii. CURRENT UCC SEARCHES............................................10
      D.    ASSUMPTION OF LEASES..............................................10
      E.    OTHER CONDITIONS..................................................10

   6.2   SELLER'S OBLIGATION:  CONDITIONS PRECEDENT...........................10

      A.    ACCURACY OF REPRESENTATIONS.......................................10
      B.    OTHER CONDITIONS..................................................10

   6.3   NON-SATISFACTION OF CONDITIONS.......................................10


7.  CLOSING...................................................................11


8.  PRORATIONS, CREDITS, CLOSING COSTS, AND CLOSING DELIVERIES................11

   8.1   PRORATION ITEMS......................................................11

      A.    REAL ESTATE TAXES AND ASSESSMENTS.................................11
      B.    UTILITY EXPENSES AND PAYMENTS.....................................12
      C.    UTILITY DEPOSITS..................................................12

   8.2   CLOSING STATEMENT AND SCHEDULES......................................12
   8.3   REPRORATION AFTER CLOSING............................................12
   8.4   SELLER'S CLOSING COSTS...............................................13
   8.5   BUYER'S CLOSING COSTS................................................13

   8.6   SELLER'S DELIVERIES..................................................13

      A.    DEED..............................................................13
      B.    BILL OF SALE......................................................14
      C.    ASSIGNMENT OF WARRANTIES AND OTHER INTERESTS......................14
      D.    WARRANTY AND OTHER ESTOPPELS......................................14
      E.    DELIVERY OF KEYS AND PROPERTY DOCUMENTS...........................15
      F.    AFFIDAVIT OF TITLE................................................15
      G.    AFFIDAVIT OF TITLE................................................15
</TABLE>


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<TABLE>
<S> <C>                                                                       <C>
      H.    CLOSING STATEMENT.................................................15
      I. EVIDENCE OF AUTHORITY................................................15
      J. REAFFIRMATION........................................................16
      K.    COMPLIANCE WITH LAND USE REQUIREMENTS.............................16

         (i)   CERTIFICATE OF OCCUPANCY.......................................16
         (ii)  LAND USE AFFIDAVIT.............................................16
         (iii) ZONING LETTER..................................................16
         (iv)  ARCHITECT/ENGINEER CERTIFICATE.................................17
         (v)   CONTRACTOR CERTIFICATE.........................................17

      L.    TRANSFER OF PERMITS...............................................17
      M.    DEVELOPER'S WARRANTY..............................................17
      N.    OPERATIONS AND MAINTENANCE MANUALS................................17
      O.    LEASE TERMINATION AGREEMENT.......................................17
      P.    OTHER INSTRUMENTS.................................................17
      Q.    TITLE AND SURVEY UPDATES..........................................18
      R.    AS BUILT DRAWINGS.................................................18
      S.    ASSUMPTION OF LEASES..............................................18
      T.    OPTION AGREEMENT..................................................18
      U.    PROPERTY MANAGEMENT AGREEMENT.....................................18

   8.7   BUYER'S DELIVERIES...................................................18

      A.    NET PURCHASE PRICE................................................18
      B.    CLOSING DOCUMENT COUNTERPARTS.....................................18
      C.    LEASE TERMINATION AGREEMENT.......................................18
      D.    OTHER INSTRUMENTS.................................................19


9.  REPRESENTATIONS AND WARRANTIES............................................19

   9.1   SELLER'S REPRESENTATIONS AND WARRANTIES..............................19

      A.    TITLE TO REAL PROPERTY............................................19
      B.    TITLE TO PERSONAL PROPERTY........................................19
      C.    ORGANIZATION, POWER AND AUTHORITY.................................19
      D.    NO UNDISCLOSED CONTRACTS..........................................20
      E.    ACCURACY AND COMPLETENESS OF OTHER PROPERTY DOCUMENTS.............20
</TABLE>


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<TABLE>
<S> <C>                                                                       <C>
      F.    COMPLIANCE OF REAL PROPERTY AND IMPROVEMENTS......................20
      G.    FLOOD, WETLANDS AND OTHER DISTRICTS...............................20
      H.    ENVIRONMENTAL MATTERS.............................................20
      I.    TAXES AND ASSESSMENTS.............................................21
      J.    CONDEMNATION PROCEEDINGS..........................................21
      K.    LITIGATION PROCEEDINGS............................................21
      L.    BANKRUPTCY........................................................21
      M.    AVAILABILITY OF UTILITIES.........................................22
      N.    DISCLOSURE........................................................22

   9.2   REAFFIRMATION AT CLOSING.............................................22
   9.3   SURVIVAL.............................................................22
   9.4   REMEDIES PRIOR TO CLOSING............................................22
   9.5   REMEDIES AFTER CLOSING...............................................23
   9.6   BUYER'S REPRESENTATIONS AND WARRANTIES...............................24

      A.    ORGANIZATION, POWER AND AUTHORITY.................................24
      B.    NO BANKRUPTCY.....................................................24


10. SELLER'S COVENANTS........................................................24

   10.1     NO ALTERATION OF TITLE............................................24
   10.2     NO ALTERATION OF SITE CONDITIONS..................................25
   10.3     COMPLIANCE WITH LAWS, LEASES, CONTRACTS...........................25
   10.4     REPRESENTATIONS AND WARRANTIES....................................25
   10.5     PERSONAL PROPERTY.................................................25
   10.6     PERMITS AND ZONING................................................26


11. NOTICES...................................................................26


12. CASUALTY AND CONDEMNATION.................................................26

   12.1     CASUALTY..........................................................26

      A.    MAJOR CASUALTY....................................................26
      B.    MINOR CASUALTY....................................................27

   12.2     CONDEMNATION......................................................27

      A.    MAJOR CONDEMNATION................................................27
</TABLE>


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<TABLE>
<S> <C>                                                                       <C>
      B.    MINOR CONDEMNATION................................................28


13. ADVISORS..................................................................28


14. INDEMNITY.................................................................28

      A.    ENVIRONMENTAL INDEMNIFICATION.....................................29
      B.    MECHANIC'S LIENS..................................................30


15. DEFAULT...................................................................30

   15.1     BUYER DEFAULT.....................................................30
   15.2     SELLER DEFAULT....................................................30


16. GENERAL PROVISIONS........................................................31

   16.1     TERMINATION.......................................................31
   16.2     EXECUTION NECESSARY...............................................31
   16.3     COUNTERPARTS......................................................32
   16.4     SUCCESSORS AND ASSIGNS............................................32
   16.5     ENTIRE AGREEMENT..................................................33
   16.6     TIME IS OF THE ESSENCE............................................33
   16.7     GOVERNING LAW.....................................................33
   16.8     SURVIVAL..........................................................33
   16.8     FURTHER ASSURANCES................................................33
   16.10    EXCLUSIVE APPLICATION.............................................33
   16.11    PARTIAL INVALIDITY................................................34
   16.12    INTERPRETATION....................................................34

      A.    DEFINED TERMS.....................................................34
      B.    PRONOUNS..........................................................34

   16.13    WAIVER RIGHTS.....................................................34
   16.14    NO IMPLIED WAIVER.................................................35
   16.15    RIGHTS CUMULATIVE.................................................35
   16.16    ATTORNEY'S FEES...................................................35
   16.17    EXHIBITS AND SCHEDULES............................................35
   16.18    CONFIDENTIALITY...................................................36
   16.19    FACSIMILE AS WRITING..............................................36
</TABLE>



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                          PURCHASE AND SALE AGREEMENT

THIS PURCHASE AND SALE AGREEMENT (this "AGREEMENT") is made and entered into as
of October 21, 1999, by and between 200 CARILLON L.L.C., a Delaware limited
liability company ("SELLER"), ECHELON INTERNATIONAL CORPORATION, a Florida
corporation ("ECHELON INTERNATIONAL" or "DEVELOPER"), and CATALINA MARKETING
SALES CORPORATION, a Delaware corporation ("BUYER").

                                R E C I T A L S:

         WHEREAS, Seller owns a certain tract or parcel of land described on
EXHIBIT A, attached hereto and made a part hereof (the "LAND") containing
approximately 6.29 acres, which Land was formerly owned by Gateway Joint
Venture, a Florida general partnership ("GATEWAY"), of which Echelon
International was a general partner; and

         WHEREAS, Gateway and Echelon International, together as Landlord, and
Buyer as Tenant, entered into a Lease Agreement ("LEASE"), and Echelon
International and Buyer entered into a Development Agreement ("LEASE DEVELOPMENT
AGREEMENT"), both dated as of July 13, 1999, pertaining to the Land and
Developer's obligations to design, construct and complete (or cause to be
designed, constructed and completed) on the Land a five (5) story office
building with approximately 142,857 rentable square feet (as measured by BOMA
1996 measurement standards for multi-tenant buildings), constructed of
structural steel frame with an architectural pre-cast concrete exterior, with
interior tenant improvements and surface and structured parking for
approximately 670 automobiles (a ratio of approximately 4.7 spaces per 1,000
rentable square feet), and other amenities and improvements as hereinafter set
forth, which development shall be known as the Catalina Marketing Building or
such other name as may be selected by Buyer ("PROJECT" or "IMPROVEMENTS"); and

         WHEREAS, Seller and Buyer have agreed that upon Developer's completion
of the Improvements, Seller and Developer shall sell to Buyer, and Buyer shall
purchase from Seller and Developer, the Land and Improvements (together, the
"Property") in accordance with the terms and provisions of this Agreement. In
contemplation of the transaction governed hereby (the "TRANSACTION"), Buyer has
also requested Developer to enter into an agreement substantially identical to
the terms and conditions of the Lease Development Agreement ("SALE DEVELOPMENT
AGREEMENT") to govern the rights, liabilities and obligations of Buyer and
Developer with respect to the design and construction of the Improvements, which
Sale Development Agreement shall conditionally control over and supersede the
rights, terms and conditions of the Lease Development Agreement until such time
that this Agreement (together with the Sale Development Agreement) is



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terminated, and Developer has agreed to enter into the Sale Development
Agreement subject to such terms and understandings; and

         WHEREAS, Seller and Echelon International are affiliated entities, and
as an inducement to Buyer to purchase the Property, Seller has caused Echelon
International to enter into the Sale Development Agreement with Buyer for the
development of the Project, and the parties understand, conform, and agree that
credits and other adjustments under the Sale Development Agreement will be
adjustments to the Purchase Price paid to Seller hereunder; and

         WHEREAS, Buyer and Seller each acknowledge and agree that the terms and
conditions of the Lease shall continue to run and be binding upon Buyer and
Seller, even in the event of the termination of this Agreement for any reason
whatsoever, until such time that the Transaction contemplated by this Agreement
closes, whereupon Buyer, Developer and Seller shall cause the Lease (and the
Lease Development Agreement) to be terminated;

         NOW, THEREFORE, for and in consideration of the promises, covenants,
representations and warranties hereinafter set forth, the sum of One Hundred
Dollars ($100.00) and other good and valuable consideration in hand paid by
Seller and Developer to Buyer and by Buyer to Seller and Developer upon the
execution of this Agreement, the receipt and sufficiency of which are hereby
acknowledged by each of Seller, Developer, and Buyer, Buyer, Developer, and
Seller hereby agree as follows:

         1.       DEFINITIONS. Wherever used in this Agreement, the following
terms shall have the meanings set forth below:

                  1.1      DEAL TERMS AND DEADLINES.

                           "ADVISOR" shall mean Cushman & Wakefield of Florida,
         Inc., which Advisor has been retained by Buyer.

                           "CLOSING DEADLINE" shall mean the date of February 7,
         2001, subject to the same adjustments of time as are made to the
         Completion Deadline and the Substantial Completion Date.

                           "CLOSING DATE" shall mean the date selected by
         Developer upon no less than ten (10) days' prior notice to Buyer, but
         in no event later than sixty (60) days after the Substantial Completion
         of all construction of the Improvements in accordance with this
         Agreement and the Sale Development Agreement (including the receipt of
         certificates of occupancy from appropriate governmental authorities
         which permit occupation of the Improvements); in no event shall the
         Closing Date be after the Closing Deadline unless



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         extended by Buyer. Developer shall use commercially reasonable, good
         faith, diligent efforts to reduce the time between Substantial
         Completion and the Closing Date, including without limitation,
         satisfying all prerequisites to Closing as quickly as possible
         following Substantial Completion.

                           "COMPLETION DEADLINE" or "SUBSTANTIAL COMPLETION
         DATE" shall mean July 7, 2000, subject to adjustment of time as
         provided herein, in the Development Agreement, or as mutually agreed by
         Developer and Buyer.

                           "PROJECT BUDGET" shall mean the development and
         construction budget for the Property set forth on EXHIBIT B, as the
         same may be amended from time to time only in accordance with this
         Agreement.

                           "PROJECT NAME" shall mean Catalina Marketing
         Building.

                           "SALE DEVELOPMENT AGREEMENT" has the meaning set
         forth in Section 4 of this Agreement.

                           "PROPERTY" shall mean the Land and Improvements.

                           "TITLE COMPANY" shall mean Lawyers Title Insurance
         Company or such other title insurance company reasonable acceptable to
         Buyer to insure Buyer's title to the Real Property.

                  1.2      STANDARD DEFINED TERMS; DEVELOPMENT AGREEMENT TERMS.
Other terms not defined herein shall have the meanings ascribed to such terms by
the Sale Development Agreement. Such terms include, but are not limited to,
"SUBSTANTIAL COMPLETION", "BASE BUILDING ARCHITECT", "BASE BUILDING CONTRACTOR",
"COST OF CONSTRUCTION", "TENANT IMPROVEMENTS ARCHITECT", "TENANT IMPROVEMENTS
CONTRACTOR", "BUYER DELAYS", "FINAL BASE BUILDING DESIGN", and "FINAL TI
DESIGN".

         2.       DEVELOPMENT, PURCHASE AND SALE. Developer agrees to develop
the Property as described herein, and Seller agrees to sell, transfer and assign
the Property to Buyer on the terms, conditions and provisions set forth in this
Agreement. Upon completion of the development of the Property, as described
below, Buyer agrees to purchase, accept and assume the Property on the terms,
conditions and provisions set forth in this Agreement.

         3.       SELLER DELIVERABLES. Buyer acknowledges that it has received
from Seller copies of the following:

                           A.       GEOTECHNICAL REPORT. Subsurface
         investigation geotechnical reports.



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                           B.       ENVIRONMENTAL REPORT. Environmental reports
         including, but not limited to, the following documents prepared by
         Dames & Moore, dated July 30, 1999.

                           C.       SURVEY. Survey of the Land, prepared by
         Polaris, Inc., bearing Job No. 001-236, last revision date August 26,
         1999.

                           D.       TITLE COMMITMENT. ALTA Commitment for Title
         Insurance, prepared by Lawyers Title Insurance Corporation, Commitment
         No. 99-06268 pertaining to the Real Property, dated September 1, 1999.

         4.       DESIGN AND CONSTRUCTION OF BUILDING AND IMPROVEMENTS.

                           4.1      DESIGN-BUILD TURNKEY PROJECT. To conform the
obligations of Buyer and Developer under the Lease Development Agreement to the
Transaction contemplated by this Agreement, Buyer and Developer have entered
into the development agreement attached hereto as EXHIBIT C (the "SALE
DEVELOPMENT AGREEMENT"). The terms and conditions, rights and liabilities
arising under the Sale Development Agreement shall control over and supersede
the Lease Development Agreement until such time that this Agreement is
terminated. Developer's use of separate entities to perform design and
construction work in no way relieves Seller of its design/build delivery
obligations.

                           A.       DEVELOPER ACKNOWLEDGMENT. Developer
         acknowledges its obligation to provide a complete and fully constructed
         Project on a turnkey delivery basis and that it is required to provide
         all items (labor, material, equipment) necessary to complete the
         Project. Omissions from the documents provided by Buyer to Developer or
         inadequate descriptions of details of the Project in such documents
         which are manifestly necessary or which are customarily performed,
         shall not release the Developer from performing such necessary or
         customary details of the Project. Developer acknowledges that the
         Project is a turnkey project and represents that it has experience with
         such project deliveries. Developer represents that it fully understands
         the general scope of work required to be performed.

         Developer further acknowledges its obligation to coordinate the design
         and construction work of each member of the Design and Construction
         Team so that all design details, plans, drawings and specifications
         adequately describe and depict the construction work. Buyer shall not
         be responsible for any changes, increased costs, claims or delays,
         except as expressly provided in the Sale Development Agreement. Buyer
         reserves the right to employ an architect and consultant of its own
         choosing to review all aspects of the Work under the Sale Development
         Agreement, including, but not limited to, the determination of
         Punchlist work.



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         4.2      PLANS AND SPECIFICATIONS FOR PROJECT.

                           A.       LEGAL REQUIREMENTS. Developer shall be
         responsible for ensuring that the Base Building Conceptual Design and
         the Final Base Building Design (the "BASE BUILDING DESIGN DOCUMENTS")
         comply in all material respects with all applicable federal, state, and
         local laws, codes, ordinances, regulations and orders in effect at the
         date of the issuance of the permit for the construction of the
         Improvements, including, but not limited to, The Americans With
         Disabilities Act ("LEGAL REQUIREMENTS"), and with any Legal
         Requirements adopted subsequent to such date to the extent necessary to
         obtain final certificates of occupancy for the Improvements.

                           B.       CERTIFICATIONS. Within five (5) days after
         receipt of the Final Base Building Design, Buyer may request
         certifications in the form of EXHIBIT D attached hereto from any or all
         members of the Design and Construction Team (or, where applicable,
         Developer's civil engineer). Developer shall use good faith, diligent
         efforts to cause the execution and delivery to Buyer of Certifications
         within twenty (20) days of Buyer's request.

                  4.3      CLAIMS

                           A.       FORCE MAJEURE. The provisions of the Sale
         Development Agreement shall govern with respect to any and all claims
         by Developer (or any member of the Design and Construction Team) of
         Force Majeure delay, Buyer Delay, Buyer - Directed Change Orders, and
         any other demand or assertion by such parties seeking an adjustment to
         the Substantial Completion Date, the Outside Delay Date, or the
         Purchase Price (a "CLAIM").

                           B.       DUTY TO PROCEED/RESOLUTION. Pending final
         resolution of a Claim, unless otherwise agreed to in writing, Developer
         shall proceed diligently with the design and construction of the
         Project.

                  4.4      MISCELLANEOUS DESIGN/CONSTRUCTION ISSUES. Buyer, in
its sole discretion, shall have the right to require changes to the Tenant
Improvement design documents. Subject to Developer's approval, which approval
shall not be unreasonably withheld or delayed, Buyer shall have the right to
direct changes to the final Base Building design documents, and to any aspect of
the Project design and construction so long as such changes do not result in a
cardinal change. Such changes shall only be valid if issued by Buyer in writing
as a Buyer-directed change order (a "BUYER-DIRECTED CHANGE ORDER"). At Closing,
Buyer will pay Developer any direct cost increases reasonably incurred as a
result of a Buyer-Directed




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Change Order. In the event this Agreement is terminated prior to Closing, Buyer
shall cause the Tenant under the Lease to pay such amount together with the rent
payment next due and owing. To the extent such Buyer-Directed Change Order
results in delay to critical path of the Detailed Critical Path Method Schedule,
it shall constitute a "Buyer Delay" under the Sale Development Agreement.

Seller and Developer shall convey to Buyer all of their respective right, title
and interest in and to the Final Base Building Design, including all copyrights
thereto. Developer is entitled only to provide copies thereof to the Base
Building Contractor (and such other Design and Construction Team members as
necessary to cause the completion of the Improvements in accordance with this
Agreement) as defined below for the sole purpose of constructing the Base
Building.

After the Final Base Building Design has been approved by Buyer, Developer may
not make any changes to it without Buyer's written approval, which approval may
be given or withheld in Buyer's sole discretion (except that Developer shall be
permitted to make changes not deemed to be material changes resulting from a
governmental official's code interpretation without the Buyer's written
approval).

In performing the Base Building construction work, Developer shall assume an
agency role, on behalf of Buyer, and act in the best interests of Buyer in
performing all Base Building-related work.

         5.       PURCHASE PRICE AND PAYMENT. The Purchase Price, subject to the
prorations and credits set forth herein, shall be due and payable as follows:

                  5.1      PURCHASE PRICE. The purchase price of the Property is
as set forth herein, subject to adjustment for unused or unauthorized
allowances. No costs, other than those set forth herein, shall be due and owing
to Seller. Any Tenant Improvements Allowance not used or authorized by Buyer
shall be deducted from the Purchase Price. The Purchase Price shall be deemed to
include the Land and Base Building, the cost of the Tenant Improvements,
Buyer-Directed Change Orders, all costs of managing the Tenant Improvements, all
costs of financing inclusive of lender's fees, appraisal, interest rate
fluctuations, lender engineering review, and all other related costs.

                           A.       LAND AND BASE BUILDING. Buyer shall pay
         Seller a lump sum, fixed price of Twenty Four Million Five Hundred
         Thousand Five Hundred Eighty Three and No/100 Dollars ($24,500,583.00)
         for the Land, and the design, construction and completion of the Base
         Building and all Base Building Systems. Except to the extent expressly
         provided elsewhere, this price includes all costs associated therewith
         including, but not limited to (1) all Land acquisition costs, (2) all
         environmental, soil, geotechnical investigations and reports, (3) all
         architect fees and design work, (4) all



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         permits, licenses, and insurance (including, without limitation,
         Buyer's owner's policy of title insurance, to be issued at closing, in
         the amount of the purchase price), (5) general and administrative
         overhead, (6) profit, (7) the Base Building construction work and
         Building Systems, (8) a reduction of $290,000.00 as consideration for
         Buyer's execution of the Property Management Agreement described in
         Section 8.6U below, and (9) all other obligations under this Agreement.

                           B.       TENANT IMPROVEMENTS. As part of the Purchase
         Price, Buyer shall pay Seller for the Tenant Improvement Work as
         follows: the cost to design and construct all Tenant Improvement Work
         calculated in accordance with Section 9 of the Sale Development
         Agreement, management fee equal to 3.5% of the total cost to design and
         construct the Tenant Improvements ("MANAGEMENT FEE"); actual
         out-of-pocket interest costs paid by Developer in connection with that
         portion of the Cost of Construction, if any, incurred after
         disbursement of the entire Tenant Improvement Allowance; and the Tenant
         Improvement Contractor Mark-Up as set forth herein. Provided, however,
         that Seller shall provide Buyer with a Tenant Improvements Allowance in
         an amount of Three Million Eight Hundred Fifty Seven Thousand One
         Hundred Thirty Nine and No/100 Dollars ($3,857,139.00) ("TENANT
         IMPROVEMENTS ALLOWANCE"). Developer shall act as Buyer's agent in
         managing the Tenant Improvements and processing invoices for the Tenant
         Improvement Architect and the Tenant Improvements Contractor, and Buyer
         shall compensate Seller with the Management Fee for such services.

                           C.       FINANCING COSTS. Developer shall provide all
         project financing through the turnover of the Project up to and
         including Closing. Except as provided in Section 5.1B above, Seller and
         Developer acknowledge and represent that the lump sum, fixed price
         stated above is the sole and exclusive compensation for all financing
         costs including, but not limited to, lenders fees, appraisal costs,
         interest rate fluctuation, lender engineering review, and all other
         costs and risks of increased costs associated with project financing.

                           D.       BUYER-DIRECTED CHANGE ORDERS. As part of the
         Purchase Price, Buyer shall pay Seller any direct cost increases
         (netted out against any direct cost reductions resulting from
         Buyer-Directed Change Orders) reasonably incurred by Developer as a
         result of Buyer-Directed Change Orders.

                  5.2      PAYMENT. At Closing, Buyer shall pay to Seller the
Purchase Price, subject to the credits, prorations and adjustments set forth
herein, in cash by federal reserve bank wire transfer to such account and bank
as Seller shall



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designate in writing to Buyer at or prior to Closing to be confirmed received in
Seller's account on or before 12:00 Noon, Tampa, Florida time on the Closing
Date, or, if no such notice is delivered by Seller to Buyer, by Federal Reserve
Funds check drawn for value received on an account in the metropolitan area in
which the Closing is to take place and dated no earlier than the day prior to
the Closing Date. Seller shall deliver to Buyer wire instructions at least 48
hours prior to closing. In addition, the amount of liquidated delay damages owed
to Buyer may be withheld.

         At Closing only minor Punchlist items shall remain, none of which shall
materially affect Buyer's ability to use any portion of the Improvements for its
intended uses. Two Hundred Percent (200%) of the value of the uncompleted work
on the Punchlist shall be escrowed at Closing. Developer shall have forty-five
(45) days after issuance of the Punchlist to complete the Punchlist Work (except
those items which reasonably require more than 45 days to complete, shall be
completed in diligent fashion, but no later than 120 days after the date the
Punchlist is issued). At the end of such cure period, Buyer shall pay Seller the
funds retained for the Punchlist Work performed (being the funds equal to 200%
of the value of the previously uncompleted work) and Seller shall forfeit the
remaining withheld funds for Punchlist Work not performed or completed, unless
Developer in good faith disputes Buyer's rejection of Punchlist Work, in which
event such funds shall continue to remain in escrow pending resolution of such
dispute.

         The parties expressly agree that if issuance of a final occupancy
permit is delayed, but that all other requirements for Substantial Completion
have been met (including without limitation that Buyer may occupy the Real
Property for the use for which it is intended under a temporary certificate of
occupancy), and Buyer has no reason to believe that the final occupancy permit
will not promptly issue upon completion of the Punchlist items, then the Closing
shall nevertheless proceed; provided that Developer's obligations under this
Agreement and the Sale Development Agreement to complete the Project and deliver
a final, unconditional certificate of occupancy, shall survive closing and be in
full force and effect. The sum of Two Hundred Fifty Thousand and No/100 Dollars
($250,000.00) shall be deducted from the Purchase Price to be paid to Seller at
Closing and escrowed at Closing until issuance of the final occupancy
certificate.

         6.       CONDITIONS TO CLOSING.

                  6.1      BUYER'S OBLIGATION: CONDITIONS PRECEDENT. The
obligation of the Buyer to consummate the Closing hereunder shall be subject to
the satisfaction at or prior to Closing of the following conditions precedent:

                           A.       ACCURACY OF REPRESENTATIONS. All of the
warranties and representations of Seller and Developer contained in this
Agreement shall be true in all material respects, in each case as of the date of
this Agreement and as of



                                       14
<PAGE>   15


the Closing Date except (i) for changes specifically permitted by this Agreement
and (ii) for those representations and warranties which expressly address
matters only as of a particular date, which representations and warranties shall
remain true and correct in all material respects as of such date.

                           B.       ENVIRONMENTAL CONDITION. On the Closing
Date, the Property shall be free of any and all Hazardous Substances either
within the Improvements or on or under the surface of the Property, except for
Hazardous Substances used in the ordinary course of Seller's construction in
strict compliance with all Environmental Laws.

                           C.       TITLE AND SURVEY UPDATES. At the time of
Closing, Seller shall possess title to the Real Property free and clear of all
encumbrances except for the Permitted Title Exceptions. In addition, at time of
Closing, Seller shall have delivered, or cause to be delivered to Buyer:

                                    i.       MARKED TITLE COMMITMENT. A "marked"
         Title Commitment, endorsed by the Title Company to (i) remove all
         references to payment of premium and charges for the policy and all
         references to expiration of the Title Commitment; (ii) indicate that
         all requirements to be performed on the part of Seller or others have
         been satisfied; (iii) delete any general survey exception (and replace
         with a reference to the specific matters shown on the Survey, as
         updated by Buyer), any exception relating to rights of parties in
         possession, and easements, liens, taxes or assessments not shown by the
         public records; and (iv) delete any exception for any matters first
         appearing of record after the date of the Commitment and prior to the
         effective date of the final policy;

                                    ii.      UPDATED SURVEY. An "as-built"
         Survey showing no matters which are not Permitted Title Exceptions.

                                    iii.     CURRENT UCC SEARCHES. All
         applicable UCC searches, dated no more than thirty (30) days prior to
         Closing, showing no matters which are not Permitted Title Exceptions
         (except for liens securing construction financing to be satisfied at
         Closing).

                           D.       ASSUMPTION OF LEASES. On or before
Substantial Completion and effective on the earlier of the commencement of the
Lease Term or Closing, Echelon Gateway, Inc. shall have assumed the existing
leasehold obligations at these certain two facilities of Buyer located on Ninth
Street, St. Petersburg, Florida, which assumption shall be guaranteed by Echelon
International or the Assignee (as defined in Section 16.4, below), and Echelon
International shall have fully cooperated with Buyer in Buyer's efforts to
obtain all required landlord and other consents in connection therewith. Echelon

                                       15
<PAGE>   16



International's obligation to cooperate shall not include any obligation to pay
money or other consideration to obtain such consents.

                           E.       OTHER CONDITIONS. Seller and Developer shall
comply with all other conditions to closing set forth elsewhere in this
Agreement.

                  6.2      SELLER'S OBLIGATION: CONDITIONS PRECEDENT. The
obligation of Seller to consummate the Closing hereunder shall be subject to the
satisfaction at or prior to Closing of the following conditions precedent:

                           A.       ACCURACY OF REPRESENTATIONS. All of the
warranties and representations of Buyer contained in this Agreement shall be
true in all material respects, in each case of the date of this Agreement and as
of the Closing Date except (i) for changes specifically permitted by this
Agreement and (ii) for those representations and warranties which expressly
address matters only as of a particular date, which representations and
warranties shall remain true and correct in all material respects as of such
date.

                           B.       OTHER CONDITIONS. Buyer shall comply with
all other conditions to closing set forth elsewhere in this Agreement.

                  6.3      NON-SATISFACTION OF CONDITIONS. If any condition set
forth in this Section 6 is not satisfied as of the date specified for
satisfaction, the party whose obligation to close is conditioned thereon may
either (a) waive satisfaction of such condition and proceed to Closing; (b)
following notice of such unsatisfied condition the other party's failure to
satisfy such condition within fifteen (15) days after such notice, elect to
terminate this Agreement and the Sale Development Agreement; or (c) if
appropriate or applicable, declare that the failure of such condition to be a
default by the other party, and, in the event of the failure of Subsections
6.1.A or 6.2.A, proceed in accordance with Section 9.4 or 9.5 hereof as
applicable, or in the event of the failure of any other condition, proceed in
accordance with the applicable provisions of Section 15.

         7.       CLOSING. Closing shall be held at 9:00 a.m. local Tampa,
Florida time, on the Closing Date at the offices of Holland & Knight LLP, 400
North Ashley, Suite 2300, Tampa, Florida 33602. Seller, Developer, and Buyer
shall conduct a "pre-closing" on the day preceding the Closing Date, in order to
finalize and execute (but not deliver, pending the Closing) the documents to be
executed and delivered at Closing. At Closing, Seller and Developer shall
deliver to Buyer the items required of such person as elsewhere set forth herein
and Buyer shall deliver to Seller the Purchase Price and the other items
required of Buyer as elsewhere set forth herein. Seller shall deliver possession
of the Property, subject only to Permitted Title Exceptions, to Buyer at the
time of Closing. The parties agree to execute and deliver into escrow the day
prior to the Closing Date all documents required for

                                       16

<PAGE>   17



Closing with funding and release of the escrow to occur on the Closing Date. If
the Transaction is not closed on or before the Closing Deadline, then either
Seller or Buyer may terminate this Agreement by written notice to the other
party; provided, however, that neither party shall have the right to terminate
this Agreement if the Closing has not occurred by the Closing Deadline as a
result of the default of the party seeking to terminate.

         8.       PRORATIONS, CREDITS, CLOSING COSTS, AND CLOSING DELIVERIES.

                  8.1      PRORATION ITEMS. In each such proration set forth
below, the portion thereof allocable to periods beginning as of the Closing
Proration Time shall be credited to Buyer, or charged to Buyer, as applicable,
and the portion thereof allocable to periods ending as of the Closing Proration
Time shall be credited to Seller, or charged to Seller, as applicable, all of
which prorations shall be made at Closing or, in the case of allocations to be
made after Closing, upon receipt of such payments or payment of such expenses.
The following items shall be prorated between Buyer and Seller or credited to
Buyer or Seller:

                           A.       REAL ESTATE TAXES AND ASSESSMENTS. All ad
         valorem real estate taxes, personal property taxes, and Carillon
         Property Owners Association assessments with respect to the Property
         for the current calendar year shall be prorated as of the Closing
         Proration Time, with due allowance for the full discount, as provided
         by law. Seller shall pay all installments for all certified and
         confirmed assessments levied upon the Property prior to Closing. In the
         event that tax bills for the current year's taxes are not available on
         the Closing Date, taxes shall be prorated based upon the tax bills for
         the previous year, or, if available, based upon the current assessed
         valuation and current millage rates, and, in such event, Seller and
         Buyer shall reprorate the taxes when actual tax bills for the current
         year are available.

                           B.       UTILITY EXPENSES AND PAYMENTS. Water, sewer,
         gas, waste fee, fire protection, electric and all other utility
         expenses and payments due or made with respect to the Property shall be
         prorated as of the Closing Proration Time, based upon the utility bills
         for the preceding period. Unless sooner transferred under the Lease,
         all such utility accounts shall be transferred to new accounts in
         Buyer's name or in the name of Buyer's designated management agent as
         of the Closing Date. Seller shall cooperate with Buyer's efforts to
         transfer such accounts and continue uninterrupted utility service to
         the Property.

                           C.       UTILITY DEPOSITS. Seller shall receive a
         credit at Closing for the amount of any utility deposits made by Seller
         and which deposits are transferred to Buyer at Closing and are
         documented to Buyer by the holder

                                       17
<PAGE>   18

thereof.

                  8.2      CLOSING STATEMENT AND SCHEDULES. On or before five
(5) days prior to the Closing Date, Buyer shall prepare and deliver to Seller a
draft Closing Statement for the Transaction, and Seller shall deliver to Buyer a
current schedule of the items and amounts to be prorated or credited as set
forth in this Section 8, including, but not limited to, ad valorem real estate
taxes and assessments (together with copies of the current or most recent
bills), all water, sewer, gas, waste fee, fire protection, electric and all
other utility expenses and payments (together with copies of the current or most
recent bills), and any utility deposits.

                  8.3      REPRORATION AFTER CLOSING. The provisions of this
Paragraph shall survive the Closing. In the event that the actual amounts of any
of the aforesaid proration items are unavailable as of the Closing Date, then
such proration shall be made on the basis of an amount reasonably estimated by
Buyer and Seller at Closing and Buyer and Seller shall thereupon reprorate such
items at such times as the exact amounts for such proration items become
available (but such prorations will be made within one year after the Closing
Date or upon such earlier date as the exact amounts for such proration become
available); provided however, that no reproration adjustment shall be made if
the net amount due is $100 or less.

                  8.4      SELLER'S CLOSING COSTS. Seller shall pay all costs
and expenses in connection with: any transfer, stamp or recording tax due in
connection with the Transaction, all reasonable title examinations and
promulgated premiums for owner's title insurance, one-half of any escrow agent
fees (if any are charged in connection with this Transaction), and the fees and
expenses of Seller's attorneys. Seller shall also be responsible for all
brokerage fees, including fees owed to Cushman & Wakefield of Florida, Inc. and
in connection therewith, Seller agrees to indemnify Buyer against any and all
claims for brokerage fees that arise by and/or through Seller from any other
entity.

                  8.5      BUYER'S CLOSING COSTS. Buyer shall pay for all
recording charges due on recordation of any documents executed in connection
with the Transaction, for the Surveys (other than the Survey previously
delivered by Seller to Buyer), and one-half of any escrow agent fees and the
fees and expenses of Buyer's attorneys.

                  8.6      SELLER'S DELIVERIES. At the Closing, Seller shall
deliver or cause to be delivered to Buyer the following (which, as to documents
to be executed by Seller or members, affiliates, or subsidiaries of Seller,
shall be duly executed and delivered):

                           A.       DEED. A Special Warranty Deed in the form of
         EXHIBIT E, containing the following:

                                       18
<PAGE>   19


                  "For the period ending twenty (20) years following the date of
                  the Deed: (i) The development, use and occupation of the Real
                  Property, and any portion thereof, shall be limited to general
                  office uses and related uses (including, without limitation,
                  training facilities, cafeteria, testing facilities, printing
                  and copying facilities, and software and hardware development
                  and assembly), (ii) all improvements located on the Real
                  Property shall not exceed in the aggregate a maximum building
                  area of 150,000 square feet of gross buildable area (as such
                  area may be increased by grantee's exercise of its expansion
                  option evidenced by that certain option agreement recorded of
                  even date); and (iii) maximum parking density located on the
                  Real Property shall not exceed five (5) parking spaces per
                  1000 square feet of gross buildable area actually constructed
                  (collectively, the "Restrictions"). The Restrictions shall be
                  binding on Buyer, its successors, successors-in-title and
                  assigns and its and their tenants, agents, employees, guests
                  and invitees, and shall run with the Real Property for a
                  period of twenty (20) years following the Date of the Deed.
                  The Restrictions are for the benefit of, and may be modified
                  or waived by an instrument executed solely by the owner of the
                  Real Property or portion thereof and by the grantor under the
                  deed or its successors or assigns, and in the event of any
                  violation or threatened violation by any owner, tenant,
                  occupant, or other person or entity having an interest in any
                  portion of the Real Property of any of the foregoing terms,
                  covenants, or Restrictions, then, in addition to all other
                  remedies provided in the deed or available by law or in
                  equity, the grantor or its successors or assigns shall have
                  the right to enjoin such violation or threatened violation."

                           B.       BILL OF SALE. A Bill of Sale (with a limited
         warranty of title from Seller and Developer), in the form of EXHIBIT F,
         subject only to the Permitted Title Exceptions, to which shall be
         attached a current inventory of all Personal Property, if any, owned by
         Seller or Developer and used solely in connection with the Real
         Property or the operation thereof.

                           C.       ASSIGNMENT OF WARRANTIES AND OTHER
         INTERESTS. An Assignment and Assumption of Warranties and Other
         Interests from Seller and Developer, in the form of EXHIBIT "G" (the
         "ASSIGNMENT OF WARRANTIES AND INTERESTS") with respect to Seller's and
         Developer's interests in Warranties and Other Interests to be assigned
         at Closing or which will be binding on Buyer or the Property, reserving
         unto Seller or Developer, as


                                       19
<PAGE>   20

         appropriate, the non-exclusive right to pursue claims under the
         Warranties and Other Interests for incomplete or defective work or
         materials, to the extent that a claim is made against such person under
         the one-year warranty in favor of Buyer or for defective or incomplete
         work or materials that may be described on Buyer's Punchlist.

                           D.       WARRANTY AND OTHER ESTOPPELS. Developer
         shall use good faith efforts to deliver to Buyer at or prior to Closing
         (i) estoppel certificates executed by Base Building Contractor, Tenant
         Improvement Contractor and their respective mechanical, electrical,
         plumbing subcontractors, and the roofing manufacturer, which estoppel
         certificates shall be substantially in the form of EXHIBIT H (a
         "WARRANTY ESTOPPEL"), and (ii) such other estoppel certificates
         requested by Buyer, in a form and substance approved by Buyer, in
         connection with covenants, conditions and restrictions, reciprocal
         easement agreements encumbering the Property and other contracts to be
         assumed by Buyer (a "COVENANT ESTOPPEL"). Notwithstanding anything
         herein to the contrary, in the event Developer is unable to obtain a
         Covenant Estoppel from the third party from whom such Estoppel has been
         requested, Developer may, at Developer's election, satisfy the
         requirement of this Paragraph D by delivering a Developer's Estoppel to
         Buyer in lieu of an estoppel signed by such third party.

                           E.       DELIVERY OF KEYS AND PROPERTY DOCUMENTS. The
         Property Documents and all keys to the Property or any portion thereof.

                           F.       NON-FOREIGN AFFIDAVIT. A certificate in the
         form of EXHIBIT I with respect to Section 1445 of the Internal Revenue
         Code stating whether or not Seller is a foreign person as defined in
         said Section 1445 and applicable regulations thereunder. Seller shall
         otherwise comply with all requirements under Section 1445 of the
         Internal Revenue Code and related provisions with respect to sales of
         real property.

                           G.       AFFIDAVIT OF TITLE. An Affidavit of Title
         with respect to liens and title matters in substantially the form of
         EXHIBIT J or otherwise as may be reasonably required by the Title
         Company.

                           H.       CLOSING STATEMENT. A Closing Statement (the
         "CLOSING STATEMENT") which shall, among other items, set forth the
         Purchase Price, all credits against the Purchase Price, the amounts of
         all prorations and other adjustments to the Purchase Price and all
         disbursements made at Closing on behalf of Buyer and Seller.

                           I.       EVIDENCE OF AUTHORITY. Evidence that Seller
         and Developer have the requisite power and authority to execute and
         deliver, and


                                       20
<PAGE>   21

         perform under, this Agreement and all documents to be signed by such
         persons in connection herewith, including, but not limited to, the
         following: (i) if such person (or any general partner or member
         thereof) is a limited liability company, a certificate duly executed by
         the members and managers of the company with respect to the offices or
         titles held by the persons who at Closing execute documents on behalf
         of such company and a certificate (duly certified by the members and
         managers of such company) with respect to the resolution of the members
         and managers of such company authorizing the company to enter into this
         Transaction, which certificate shall also recite that the resolution
         has been duly and unanimously adopted by the company and remains in
         full force and effect; (ii) if such person (or any general partner or
         member thereof) is a corporation, an incumbency certificate duly
         executed by the secretary or assistant secretary of the corporation
         with respect to the offices held by the persons who at Closing execute
         documents on behalf of such corporation and a certificate (duly
         certified by the secretary or assistant secretary of such corporation)
         with respect to the resolution of the Board of Directors of such
         corporation authorizing the corporation to enter into this Transaction,
         which certificate shall also recite that the resolution has been duly
         and unanimously adopted by the Board of Directors and remains in full
         force and effect; and (iii) if such person (or any general partner or
         member thereof) is a partnership, such person shall deliver to Buyer a
         certified copy of the partnership agreement and partnership
         certificate, together with all amendments and modifications thereof, of
         any partnership which is the person or a general partner of the person,
         together with duly executed and delivered consents of the partners
         thereof with respect to the Transaction, to the extent such consents
         are or may be necessary under such agreements.

                           J.       REAFFIRMATION. A reaffirmation of the
         representations, warranties and covenants set forth in Section 9 hereof
         in the form of EXHIBIT K and made a part hereof, subject to the
         limitations on survival as provided hereinafter; and in the event a
         change in facts and circumstances requires a change in any such
         representation or warranty, the certificate shall specify any such
         changes in reasonable detail.

                           K.       COMPLIANCE WITH LAND USE REQUIREMENTS. The
         originals (or, to the extent originals are not available, copies) of
         all of the Land Use Compliance Documents, to the extent in Seller's or
         Developer's possession and not theretofore delivered to Buyer. Seller
         and Developer shall use commercially reasonable efforts to obtain the
         following items prior to Closing, all of which shall be subject to the
         reasonable approval of Buyer in all respects (collectively referred to
         as the "LAND USE COMPLIANCE DOCUMENTS"):

                                    (i)      CERTIFICATE OF OCCUPANCY. Final
                  certificate of


                                       21
<PAGE>   22

                  completion and occupancy (as applicable) from the governmental
                  authorities administering compliance with Land Use
                  Requirements which permits occupancy of the Improvements. To
                  the extent only conditional certificates of completion or
                  occupancy (as applicable) are available as of the Closing
                  Date, Developer shall deliver to Buyer final certificates of
                  completion or occupancy (as applicable), as and when the same
                  are issued.

                                    (ii)     LAND USE AFFIDAVIT. An affidavit
                  from officers of Developer familiar with the Property in the
                  form of EXHIBIT L, stating that to such persons' Knowledge all
                  of the Property and Improvements comply with all Land Use
                  Requirements.

                                    (iii)    ZONING LETTER. Certificates of
                  compliance, in the form of EXHIBIT M, or such other form as
                  customarily delivered by the governmental agency having
                  jurisdiction thereover.

                                    (iv)     ARCHITECT/ENGINEER CERTIFICATE. A
                  certificate from an architect and an engineer (if Developer
                  has employed an engineer with respect to the Property)
                  licensed to practice in the State in which the Property is
                  located in the form of EXHIBIT N.

                                    (v)      CONTRACTOR CERTIFICATE. A
                  certificate from both the Base Building Contractor and the
                  Tenant Improvement Contractor, in the form of EXHIBIT O.

         Land Use Compliance Documents submitted to Buyer prior to execution of
         this Agreement shall be updated to a date not earlier than forty five
         (45) days prior to Closing.

                           L.       TRANSFER OF PERMITS. If applicable, Seller
and Developer shall execute all applications and instruments required in
connection with the transfer of all Permits, to the extent transferable, and to
the extent applicable to the Real Property, only, in order to transfer the
benefits of each such Permit to the Buyer. To the extent any Permit pertains to
land in addition to the Real Property, Seller or Developer, as appropriate,
shall use commercially reasonable efforts to obtain a modification of such
Permit, in form and substance reasonably acceptable to Buyer or as otherwise
mandated by the agency issuing the permit, running solely to the Real Property.

                           M.       DEVELOPER'S WARRANTY. At Closing, Developer
shall execute and deliver to Buyer a warranty in the form of EXHIBIT P attached
hereto and made a part hereof, which warranty shall warrant and guarantee

                                       22
<PAGE>   23

the Improvements for a period of one (1) year from the date of Closing.

                           N.       OPERATIONS AND MAINTENANCE MANUALS. At
         closing, Seller or Developer shall deliver three (3) bound copies of
         the Operations and Maintenance Manuals for all major items in the
         Building, including systems and equipment, and the originals of all
         manufacturers', suppliers' and other third party warranties and
         guarantees for any Project item.

                           O.       LEASE TERMINATION AGREEMENT At Closing
         Developer shall execute, and cause Gateway Joint Venture to execute, an
         agreement terminating the Lease and the Lease Development Agreement.

                           P.       OTHER INSTRUMENTS Such other instruments or
         documents as may be reasonably requested by Buyer or the Title Company,
         or reasonably necessary, to effect or carry out the purposes of this
         Agreement (which funds, instruments or documents shall be subject to
         Seller's or Developer's prior approval thereof, as appropriate, which
         approval shall not be unreasonably withheld or delayed).

                           Q.       TITLE AND SURVEY UPDATES. Updates of the
Title Commitment and survey in accordance with Section of 6.3A.

                           R.       AS BUILT DRAWINGS. All as-built drawings for
the Base Building and the Tenant Improvements.

                           S.       ASSUMPTION OF LEASES. The Assumption of
Leases in the form of EXHIBIT Q.

                           T.       RESTRICTION MODIFICATION OPTION AGREEMENT.
An agreement granting Buyer or its successors or assigns the option to purchase
the right to construct up to 100,000 square feet of additional development on
the Property at the price of $12.00 per square foot, which agreement shall be in
the form provided by Developer and reasonably acceptable to Buyer.

                           U.       PROPERTY MANAGEMENT AGREEMENT. A property
management agreement providing for Developer's management of the Property with
service commensurate with other Class "A" office buildings in the
Gateway/Westshore office markets, for a term of five (5) years, noncancellable
absent cause, for a fee of Ninety Thousand and No/100 Dollars ($90,000.00) for
the first year, increasing three percent (3%) per year, otherwise in form and
substance satisfactory to Seller, Developer, and Buyer.

                  8.7      BUYER'S DELIVERIES. At the Closing, Buyer shall
deliver or cause to be delivered to Seller the following:

                                       23
<PAGE>   24

                           A.       NET PURCHASE PRICE. The Purchase Price due
         at Closing under this Agreement, subject to the right to withhold
         monies for Punchlist Work and liquidated delay damages as provided in
         Section 4 of this Agreement or the Sale Development Agreement.

                           B.       CLOSING DOCUMENT COUNTERPARTS. Executed
         counterparts of the Closing Statement.

                           C.       LEASE TERMINATION AGREEMENT. Buyer shall
         execute an agreement terminating the Lease and Lease Development
         Agreement.

                           D.       OTHER INSTRUMENTS. Such other funds,
         instruments or documents as may be reasonably requested by Seller,
         Developer, or the Title Company, or reasonably necessary, to effect or
         carry out the purposes of this Agreement (which funds, instruments or
         documents shall be subject to Buyer's prior approval thereof, which
         approval shall not be unreasonably withheld or delayed).

         9.       REPRESENTATIONS AND WARRANTIES.

                  9.1      SELLER'S AND DEVELOPER'S REPRESENTATIONS AND
WARRANTIES. Seller and Developer, as of the date of the execution of this
Agreement by such person (or such other date as may be specified hereinafter),
and as of Closing, represent and warrant to Buyer, and covenant with Buyer,
subject to the matters on the Representation Exception Schedule, as follows:

                           A.       TITLE TO REAL PROPERTY. To Seller's and
         Developer's Knowledge, there are no other encumbrances to the title of
         the Real Property other than the Lease and other than as described in
         the Title Commitment.

                           B.       TITLE TO PERSONAL PROPERTY. Seller or
         Developer is the owner of the Personal Property free and clear of all
         encumbrances except for the Permitted Title Exceptions.

                           C.       ORGANIZATION, POWER AND AUTHORITY. Echelon
         International is a Florida corporation, duly organized, validly
         existing and in good standing under the laws of the State of Florida
         and has all necessary power to execute and deliver this Agreement and
         perform all its obligations hereunder. 200 Carillon L.L.C. is a Florida
         limited liability company, duly organized, validly existing and in good
         standing under the laws of the State of Florida. Each of Seller and
         Developer has the full power and authority to enter into and perform
         this Agreement, and the execution, delivery and performance of this
         Agreement by such persons (i) has been duly and validly


                                       24
<PAGE>   25


         authorized by all necessary action on the part of such persons, (ii)
         does not conflict with or result in a violation of such person's
         articles of organization (or by-laws), or any judgment, order or decree
         of any court or arbiter in any proceeding to which such person is a
         party, and (iii) does not conflict with or constitute a material breach
         of, or constitute a material default under, any contract, agreement or
         other instrument by which such person is bound or to which it is a
         party. This Agreement is the valid and legally binding obligation of
         Seller and Developer enforceable in accordance with its terms.

                           D.       NO UNDISCLOSED CONTRACTS. As of Closing,
         there shall be no management, real estate, leasing or rental
         commission, service, maintenance, employment, union or other service
         contracts of any kind or description in existence relating to the
         Property and binding on Buyer, except for service contracts for
         elevators and other necessary services under terms reasonably
         acceptable to Buyer.

                           E.       ACCURACY AND COMPLETENESS OF OTHER PROPERTY
         DOCUMENTS. Developer has furnished Buyer with complete copies of the
         following documents: (1) soils reports, and (2) geotechnical report
         dated May 21, 1999, prepared by Ardaman & Associates, Inc. ("Property
         Documents"), and all modifications, additions and deletions to any of
         the foregoing; with respect to each, to Seller's or Developer's
         Knowledge they have not been changed, further assigned or further
         amended except for amendments, if any, copies of which have been
         provided to Buyer.

                           F.       COMPLIANCE OF REAL PROPERTY AND
         IMPROVEMENTS. The Property is in compliance in all material respects
         with all existing fire, health, building, handicapped persons,
         environmental, sanitation, use and occupancy or zoning laws and all
         other Legal Requirements applicable to the Property. Developer has
         obtained all Permits required for the construction of the Improvements.
         The Property is not dependent upon any other parcel of real property
         for parking or open space in compliance with any code, law, ordinance,
         statute, rule or regulation. The Improvements, when completed, will
         require no more than 660 parking spaces in order to meet all parking
         requirements of the governmental authority having jurisdiction over the
         Property.

                           G.       FLOOD, WETLANDS AND OTHER DISTRICTS. The
         Land (i) lies within special flood hazard areas "A" and "V" as
         determined by the United States Department of Housing and Urban
         Development and FEMA, and (ii) does not contain a wetlands area as
         determined by the Army Corps of Engineers, or any other area or
         designation by any other governmental or quasi-governmental authority
         as an area subject to environmental, archeological or other regulation
         that would materially affect the current or


                                       25
<PAGE>   26

         proposed use of the Property.

                           H.       ENVIRONMENTAL MATTERS. Developer has
         delivered to Buyer a copy of that certain Environmental Report
         performed by Dames & Moore dated July 30, 1999 (the "ENVIRONMENTAL
         REPORTS"). There are no existing violations of federal, state or local
         laws, regulations, ordinances or orders related to environmental
         matters relating to the ownership, use, condition, or operation of the
         Real Property. No written or oral notice from any court or governmental
         agency, official or instrumentality, of any alleged violation of any
         ordinance, law, decree, order, code, or governmental rule or regulation
         relating to environmental matters has been filed or communicated to
         Seller with respect to the ownership, use, condition, or operation of
         the Real Property or any part thereof. No release, discharge, spillage
         or disposal of any Hazardous Substance has occurred or is occurring on
         the Real Property and no soil or water in or under any of the Real
         Property has been contaminated by any Hazardous Substance (except for
         contamination which may occur during construction but which has been
         fully remediated in accordance with all Legal Requirements prior to
         Closing).

                           I.       TAXES AND ASSESSMENTS. The Property is
         separately assessed for real property tax assessment purposes and is
         not combined with any other real property for such tax assessment
         purposes. Seller has received no written notice of any contemplated or
         actual re-assessments of the Property or any part thereof for general
         real estate tax purposes. To Seller's or Developer's Knowledge, no
         assessments for public improvements, impact fees or similar exactions
         have been made against the Property which remain unpaid as of Closing.

                           J.       CONDEMNATION PROCEEDINGS. There are no
         pending or threatened Condemnation Proceedings which would affect the
         Property, or any part thereof.

                           K.       LITIGATION PROCEEDINGS. There are no
         judgments unsatisfied against Seller or the Property or consent decrees
         or injunctions to which the Property is subject, and there is no
         litigation, claim or proceeding pending or, to Seller's or Developer's
         Knowledge, threatened against or relating to the Property, nor does
         Seller or Developer know of any basis for any such action or of any
         governmental investigation relative to the Property. Seller and
         Developer have no knowledge of the existence of criminal investigation
         concerning Seller or Developer which will have a material adverse
         affect on its ability to perform under this Agreement, the Property or
         the use and operation of the Property.

                           L.       BANKRUPTCY. Neither Seller nor Developer
         have


                                       26
<PAGE>   27

         (A) commenced a voluntary case, or had entered against it a petition,
         for relief under any federal bankruptcy act or any similar petition,
         order or decree under any federal or state law or statute relative to
         bankruptcy, insolvency or other relief for debtors, (B) caused,
         suffered or consented to the appointment of a receiver, trustee,
         administrator, conservator, liquidator or similar official in any
         federal, state or foreign judicial or non-judicial proceeding, to hold,
         administer and/or liquidate all or substantially all of its assets, (C)
         made an assignment for the benefit of creditors.

                           M.       AVAILABILITY OF UTILITIES. As of Closing,
         all public utilities (sanitary sewer, storm sewer, electricity, water
         and telephone) required for the operation of the proposed Improvements
         to the Property will be installed and operating, and all installation
         and connection charges and all tap-on, permit or other fees required as
         a precondition to such utility service will be paid in full. Neither
         Seller nor Developer have received any notice of a claim with respect
         to storm water flow from any owner of adjacent property or otherwise.
         All such public utilities either enter the Land through adjoining
         public streets or, if they pass through adjoining private land, do so
         in accordance with valid and recorded public easements or private
         easements which will inure to the benefit of Buyer.

                           N.       DISCLOSURE. No statement, warranty or
         representation by Seller or Developer herein contains an untrue
         statement of material fact, or omits to state a true statement of
         material fact necessary in order to make such statement, warranty or
         representation not misleading in light of the circumstances under which
         such statement, warranty or representation is made.

                  9.2      REAFFIRMATION AT CLOSING. All of the foregoing
representations, warranties and covenants of Seller and Developer shall be
reaffirmed by such persons in writing at Closing subject to the Survival Period,
to the extent the facts and circumstances in existence as of Closing permit such
reaffirmation, and in the event a change in facts and circumstances requires a
change in any such representation or warranty, the certificate shall specify any
such changes in reasonable detail.

                  9.3      SURVIVAL. The representations, warranties and
covenants set forth above shall survive Closing hereunder for a period of one
(1) year (the "SURVIVAL PERIOD"), provided claims are asserted against Seller or
Developer within such one (1) year period.

                  9.4 REMEDIES PRIOR TO CLOSING. If it is determined at any time
prior to Closing that any of the foregoing representations and warranties of
Seller or Developer were not accurate in any material respect either as of the
date made or

                                       27
<PAGE>   28

as of the Closing Date, then, unless Seller or Developer cures such inaccuracy
to Buyer's reasonable satisfaction (by paying money and performing any act or
acts necessary to do so) on or before thirty (30) days after written notice from
Buyer to Seller or Developer of such inaccuracy (but in no event later than the
Closing Deadline), then Buyer shall elect either of the following remedies,
which shall be Buyer's sole and exclusive remedies: (i) the Purchase Price shall
be reduced by an amount equal to the cost to cure the impact of such inaccuracy,
or if not curable, equal to the diminution in the Property's value resulting
from such inaccuracy, as determined by: (a) mutual agreement of Buyer, Seller,
and Developer, or (b) if Buyer and Seller fail to agree within ten (10) days
after notice from one party to the other of such inaccuracy of any
representation or warranty, by arbitration in accordance with Section 13 of the
Sales Development Agreement, except that the "ADR Arbiter" shall be a Florida
certified appraiser who is a member of the Appraisal Institute, with at least
ten (10) years experience in appraising office properties in the Tampa Bay area;
or, alternatively, and provided the inaccuracy materially reduces the usefulness
of the Property to Buyer, but in no event shall such reduction of the Purchase
Price under this Section 9.4(i) exceed One Hundred Fifty Thousand and No/100
Dollars ($150,000.00) in the aggregate, or (ii) Buyer shall have the right to
terminate this Agreement and the Sale Development Agreement by delivery of
written notice to Seller and seek reimbursement from Seller of Buyer's
reasonable actual out-of-pocket expenses incurred in connection with the
Transaction up to a maximum amount of One Hundred Fifty Thousand and No/100
Dollars ($150,000.00), prior to the date of such termination. Notwithstanding
the foregoing, the above limitations of damages shall not be applicable to any
contribution rights under state or federally mandated environmental remediation.

                  9.5      REMEDIES AFTER CLOSING. If it is determined at any
time after Closing and prior to expiration of the Survival Period that any of
the foregoing representations and warranties of Seller or Developer were not
accurate in any material respect either as of the date made or as of the Closing
Date (or as reaffirmed at Closing), then, provided that Buyer has delivered
written notice to Seller or Developer of such inaccuracy prior to the expiration
of the Survival Period, unless Seller or Developer cures such inaccuracy to
Buyer's reasonable satisfaction (by paying money and, as applicable, performing
any act or acts necessary to do so) on or before thirty (30) days after such
written notice from Buyer of such inaccuracy (or provided Seller or Developer
have commenced such cure and are diligently prosecuting the same to completion,
such additional to as is reasonably necessary to complete such cure, not to
exceed ninety (90) days), Seller and Developer shall be liable to Buyer with
respect to such inaccuracy in such representations and warranties to the extent
the same has a material adverse impact on the value, ownership, or use of the
Property, and Buyer shall be entitled to seek a claim for Buyer's actual damages
(including without limitation, any increased costs in financing the purchase of
the Property), but otherwise excluding consequential


                                       28
<PAGE>   29

damages, incurred on account of such inaccuracy, not to exceed the sum of One
Hundred Fifty Thousand and No/100 Dollars ($150,000.00) in the aggregate.
Notwithstanding the foregoing, the above limitation of damages shall not be
applicable to any contribution rights under state or federally mandated
environmental remediation.

                  9.6      BUYER'S REPRESENTATIONS AND WARRANTIES. Buyer, as of
the date of the execution of this Agreement by Buyer, represents and warrants to
Seller as follows, and as a condition precedent to Seller's obligation to sell
the Property to Buyer at Closing under this Agreement, the following
representations of Buyer shall be true and correct in all material respects as
of the Closing Date:

                           A.       ORGANIZATION, POWER AND AUTHORITY. Buyer is
         a corporation and is duly organized and validly existing and in good
         standing under the laws of Delaware, and has the power and authority to
         enter into and perform its obligations under this Agreement. Buyer has
         the full power and authority to enter into this Agreement and the
         execution and delivery of this Agreement by Buyer (i) has been duly and
         validly authorized by all necessary action on the part of Buyer, and
         (ii) to the knowledge of the officer of Buyer signing this Agreement,
         does not conflict with or result in a violation of Buyer's Articles of
         Incorporation or By-Laws or any judgment, order or decree of any court
         or arbiter in any proceeding to which Buyer is a party, and (iii) to
         the knowledge of the officer of Buyer signing this Agreement, does not
         conflict with or constitute a material breach of, or constitute a
         material default under, any contract, agreement or other instrument by
         which Buyer is bound or to which it is a party.

                           B.       NO BANKRUPTCY. Buyer has not (A) commenced a
         voluntary case, or had entered against it a petition, for relief under
         any federal bankruptcy act or any similar petition, order or decree
         under any federal or state law or statute relative to bankruptcy,
         insolvency or other relief for debtors, (B) caused, suffered or
         consented to the appointment of a receiver, trustee, administrator,
         conservator, liquidator or similar official in any federal, state or
         foreign judicial or non-judicial proceeding, to hold, administer and/or
         liquidate all or substantially all of its assets, or (C) made an
         assignment for the benefit of creditors.

         10.      SELLER'S AND DEVELOPER'S COVENANTS. Seller and Developer agree
that between the date hereof and the Closing Date:

                  10.1     NO ALTERATION OF TITLE. Except as provided
hereinafter, Seller shall not, so long as this Agreement remains in effect,
permit further encumbrance of title to the Property after the date hereof
without the prior written consent of Buyer, which consent shall not be
unreasonably withheld. Without limiting the


                                       29
<PAGE>   30

foregoing, Seller shall permit the encumbrance of the Property, or any portion
thereof or any interest therein, except as follows: Seller shall be permitted to
make the following conveyances: (a) encumbrances in accordance with the Plans
and Specifications of utility easements to utility companies, which utility
easements shall serve only the Property, but provided that all such easements
affecting the Property shall be submitted to Buyer for approval, which approval
shall not be unreasonably withheld or delayed, prior to the execution thereof by
Seller, accompanied by a survey showing the location thereof; (b) a deed of
trust or mortgage and security agreement to secure the Construction Loan from
Construction Lender to Developer or Seller (and any amendments, modifications,
or renewals thereof), which indebtedness shall in no event exceed the Purchase
Price Limit; (c) any claim of lien, notice of commencement or judgment provided
Seller causes such encumbrance to be terminated or bonded off prior to Closing;
or (d) any amendment to the restrictions, covenants and conditions described in
Item 9, Schedule B, Section 2 of the Title Commitment appointing a successor
developer or clarifying the legal description of an existing easement not
encumbering the Property.

                  10.2     NO ALTERATION OF SITE CONDITIONS. Seller covenants
that, other than as expressly contemplated under the Lease Development
Agreement, the Sale Development Agreement and this Agreement, Seller will not
permit any material adverse change to the condition at the Project site
including, but not limited to, environmental conditions.

                  10.3     COMPLIANCE WITH LAWS, LEASES, CONTRACTS. Seller shall
comply in all material aspects with, make all payments required to be paid
under, and suffer no default under: (i) all laws, ordinances, regulations and
orders relating to the Property, and (ii) all Record Exceptions.

                  10.4     REPRESENTATIONS AND WARRANTIES. Seller and Developer
shall not take any action which could make any of the representations and
warranties of Seller or Developer under this Agreement untrue or inaccurate in
any material respect or fail to take any action necessary to prevent any of the
representations and warranties of Seller or Developer from becoming untrue or
inaccurate in any material respect. Seller or Developer, as applicable, shall
notify Buyer promptly in writing if prior to the Closing Date such person has
knowledge of (within the definition of "SELLER'S OR DEVELOPER'S KNOWLEDGE") any
fact, transaction, event or occurrence which could make any of the
representations and warranties of Seller or Developer under this Agreement not
true and correct (without regard to any knowledge qualification set forth with
respect thereto) in all material respects.

                  10.5     PERSONAL PROPERTY. Seller and Developer shall not
remove any of the Property, including Personal Property, from the Real Property
or the Improvements nor use any of the Personal Property prior to the Closing
Date except


                                       30
<PAGE>   31

such use thereof as is normal and customary in the operation and maintenance of
the Property. Seller and Developer covenants that items of Personal Property
which consist of inventory and maintenance items shall be maintained at the
customary level for Class A operations and will be available and conveyed to
Buyer on the Closing Date.

                  10.6     PERMITS AND ZONING. Developer shall use its
commercially reasonable efforts to preserve in force all existing Permits and to
renew all Permits expiring prior to the Closing Date on terms reasonably
acceptable to Buyer. If any such Permit shall be suspended or revoked, Developer
shall promptly notify Buyer and shall diligently take all measures reasonably
necessary to cause the reinstatement of such Permit without any additional
limitation or condition. Developer shall not seek or allow any amendment to any
Permit which would alter the existing permissible uses of the Property or any
part thereof. Without the prior written consent of Buyer, which consent may be
withheld in Buyer's sole discretion reasonably exercised, Seller and Developer
shall not apply for, consent to, promote or acquiesce in any modification of any
zoning restrictions or other restrictions or regulations of governmental or
quasi-governmental authorities with respect to the Property.

         11.      NOTICES. All notices, consents, approvals and other
communications which may be or are required to be given by either Seller,
Developer or Buyer under this Agreement shall be given in the manner provided in
the Sale Development Agreement.

         12.      CASUALTY AND CONDEMNATION.

                  12.1     CASUALTY. In the event that prior to the Closing Date
any portion of the Improvements is damaged or destroyed by fire or other
casualty, then Seller shall immediately deliver written notice to Buyer of such
casualty (hereinafter referred to as "SELLER'S CASUALTY NOTICE") and the
following provisions shall apply with respect to such casualty:

                           A.       MAJOR CASUALTY. If such damage or
         destruction results in a casualty loss in an amount exceeding One
         Million and No/100 Dollars ($1,000,000) (the "DAMAGE LIMIT"), then,
         Buyer shall have the right to terminate this Agreement and the Sale
         Development Agreement unless prior to Closing the damaged or destroyed
         improvements have been restored or replaced in a manner that meets or
         exceeds the original Plans and Specifications and is otherwise in full
         compliance with this Agreement or, at Buyer's option, Buyer and Seller
         shall use good faith efforts to enter into contractual arrangements for
         such restoration or replacement. Any such termination shall be effected
         by written notice to Seller received within ten (10) days after Buyer
         has received Seller's Casualty Notice, in which event

                                       31

<PAGE>   32

         thereafter neither party hereto shall have any further rights,
         obligations or liabilities hereunder except to the extent that any
         right, obligation or liability set forth herein expressly survives
         termination of this Agreement. In the event that this Agreement and the
         Sale Development Agreement are not terminated pursuant to this
         Subparagraph A, Developer shall use due diligence and good faith to
         repair such damage and complete construction of the Improvements as
         quickly as possible.

                           B.       MINOR CASUALTY. If such damage or
         destruction results in a casualty loss in an amount not exceeding the
         Damage Limit, (i) Buyer shall have no right to terminate this Agreement
         or the Sale Development Agreement on account thereof, and (ii)
         Developer shall use due diligence and good faith to repair such damage
         and complete construction of the Improvements as quickly as possible.

                  12.2     CONDEMNATION. In the event that prior to the Closing
Date there shall be commenced or instituted against the Property any
Condemnation Proceeding, Seller shall immediately give written notice
(hereinafter referred to as "SELLER'S CONDEMNATION NOTICE") of such Condemnation
Proceeding to Buyer, and:

                           A.       MAJOR CONDEMNATION. In the event that such
         Condemnation Proceeding would result in the taking of any portion of
         any Improvement (other than taking of paving or curbing, so long as
         such taking of paving or curbing does not limit access to the
         Property), or any other taking which materially affects the Property in
         Buyer's reasonable opinion, or any portion of the Property worth in
         excess of Five Hundred Thousand and No/100 Dollars ($500,000), then
         Buyer shall have the right to terminate this Agreement and the Sale
         Development Agreement by written notice to Seller and Developer
         received within ten (10) days after the receipt of Seller's
         Condemnation Notice, in which event thereafter neither party hereto
         shall have any further rights, obligations or liabilities hereunder
         except to the extent that any right, obligation or liability set forth
         herein expressly survives termination of this Agreement. In the event
         that Buyer shall not elect to terminate this Agreement and the Sale
         Development Agreement pursuant to this Subparagraph A: (i) the
         conveyance of the Property shall be less such portion of the Property
         so taken (or shall be subject to, as applicable) said Condemnation
         Proceeding without adjustment of the Purchase Price, (ii) Seller shall
         assign or pay to Buyer at Closing all of such person's right, title and
         interest, if any, in any award payable on account of such Condemnation
         Proceeding or pay to Buyer all such awards previously paid, and (iii)
         neither Seller nor Developer shall be obligated to repair or restore
         the damage to the Property arising on account of said Condemnation
         Proceeding.


                                       32
<PAGE>   33

                           B.       MINOR CONDEMNATION. In the event that such
         Condemnation Proceeding would not involve the taking of any portion of
         any Improvement described in subparagraph A above: (i) Buyer shall have
         no right to terminate this Agreement and the Sale Development Agreement
         on account thereof, (ii) the conveyance of the Property shall be less
         such portion of the Property so taken (or shall be subject to, as
         applicable) said Condemnation Proceeding without adjustment of the
         Purchase Price, (iii) Seller shall assign to Buyer at Closing all of
         Seller's right, title and interest, if any, in any award payable, and
         pay to Buyer all such awards previously paid, on account of such
         Condemnation Proceeding, and (iv) neither Seller nor Developer shall be
         obligated to repair or restore the damage to the Property arising on
         account of said Condemnation Proceeding.

         13.      ADVISORS. Each party represents to the other that such party
has not incurred any obligation to any broker or real estate agent with respect
to the purchase or sale of the Property except for the Advisor defined above and
Echelon Real Estate Services, Inc. ("ERES"), which obligation has been incurred
by [SELLER] pursuant to a separate agreement with the Advisor and ERES executed
in connection with the sale/lease of the Property. Seller shall, upon the
Closing of this Transaction and receipt by Seller of the Purchase Price, pay to
Advisor and ERES the appropriate sales commission pursuant to the terms of the
brokerage agreement with Advisor and ERES. Except for Advisor and such
commission payable as set forth above, Seller, Developer, and Buyer each hereby
(a) represent and warrant to the other that it has not employed, retained or
consulted any broker, agent, or finder in carrying on a negotiation in
connection with this Agreement or the Transaction, and (b) indemnify and agree
to hold the other harmless from and against any and all claims, demands, causes
of action, debts, liabilities, judgments and damages (including costs and
reasonable attorneys' fees actually incurred in connection with the enforcement
of this indemnity) which may be asserted or recovered against the indemnified
party on account of any brokerage fee, commission or other compensation arising
by reason of the indemnitor's breach of this representation and warranty.
Advisor is being paid a real estate brokerage commission pursuant to a separate
agreement between Seller and Advisor. This Paragraph shall survive the Closing
or any termination of this Agreement.

         14.      INDEMNITY. Each of Seller and Developer shall and does
protect, defend, indemnify and save Buyer harmless for, from and against all
Loss imposed upon or asserted against Buyer by reason of: (a) any claim by a
third party against Buyer arising out of any activity, construction,
development, occupancy, use or non-use of the Property arising or occurring
before the Closing (other than any activity, construction, development,
occupancy, and use of the Property by Buyer or buyer's agents, employees or
contractors) or in any way related to or arising out of any act, omission,
contract or commitment of Seller or Developer, or its agents,

                                       33
<PAGE>   34
employees or contractors, at any time before or after the Closing; (b) any
accident, injury to or death of person (including workmen) or loss or damage to
property occurring on or about the Property arising or accruing before the
Closing, unless due to the negligence or willful acts of Buyer or Buyer's
agents, employees or contractors; and (c) subject to the limitations on remedies
in favor of Buyer as may be specified in this Agreement, any loss or damage to
Buyer resulting from any material breach or default by Seller or Developer of
any obligation or covenant of Seller under this Agreement or under any document,
instrument or agreement delivered pursuant to this Agreement. In the event Buyer
shall be made a defendant in any action, suit or proceeding brought by reason of
any such occurrence, Seller and Developer, at such parties' own expense, shall
defend or cause to be defended such action, suit, or proceeding or cause the
same to be resisted and defended by counsel designated by such parties or its
insurer and reasonably approved by Buyer. If any such action, suit or
proceedings should result in final judgment against Buyer, Seller, and Developer
shall promptly satisfy and discharge such judgment or cause such judgment to be
promptly satisfied and discharged. The obligations of Seller and Developer under
subsection (a) of this Paragraph shall survive the Closing, and the obligations
of Seller and Developer under subsections (a) and (c) shall survive the Closing
for a period of one (1) year provided any claim under those subsections are
asserted against Seller or Developer within such one (1) year period.

                           A.       ENVIRONMENTAL INDEMNIFICATION. In addition
         to other obligations hereunder, each of Seller and Developer agrees to
         indemnify Buyer and its lender, consultants, officers, and employees,
         successors and assigns from and against all demands, claims, civil or
         criminal actions or causes of action, liens, assessments, penalties, or
         fines, losses, damages, liabilities, or obligations, costs,
         disbursements, expenses or fees of any nature (including without
         limitation clean up costs, attorneys fees, paralegal fees, consultant
         fees or expert fees and disbursements and costs of litigation at trial
         and appellate levels) which may at any time be imposed upon, incurred
         by, asserted or awarded against Buyer directly or indirectly related to
         or resulting from all conditions (including those caused during
         construction) which existed at the Property site prior to the date on
         which the Buyer occupies the completed Improvements on the site. This
         environmental indemnification shall be in full force and effect until
         one (1) year after Substantial Completion of the entire Project. Seller
         and Developer shall provide a separately executed document evidencing
         its agreement to this environmental indemnification.

                           B.       MECHANIC'S LIENS. Each of Seller and
         Developer agrees to indemnify and to hold Buyer harmless from and
         against all loss, claims, resulting from, in whole or in part failure
         to comply with requirements of Fla. Statute ss.713.23 including but not
         limited to Notice of Commencement and


                                       34
<PAGE>   35

         Bond. After closing, each of Seller and Developer shall and does
         protect, defend and indemnify and hold Buyer harmless for, from and
         against all loss, claims, liens, causes of actions, proceedings,
         liabilities, fees (including attorneys fees), judgment, executions,
         claims and demands of whatever nature from the Base Building Contractor
         or the Tenant Improvement Contractor or their subcontractors,
         sub-subcontractors or anyone claiming through, or as a result of, a
         contract or agreement with the Base Building Contractor or the Tenant
         Improvement Contractor for the performance of work or furnishing of
         services, materials or equipment of any kind for the project.

         15.      DEFAULT.

                  15.1     BUYER DEFAULT. In the event that Buyer defaults in
the observance or performance of its covenants and obligations hereunder, and
such default continues for ten (10) consecutive days after the date of receipt
of written notice from Seller demanding cure of such default, or such longer
period as may be reasonably required to effect a cure (but in no event to exceed
a total of ninety (90) days), Seller shall be entitled, as its sole remedy, if
Seller has theretofore complied with Seller's obligations under this Agreement,
to terminate this Agreement and the Sale Development Agreement by written notice
to Buyer of such termination. Seller's agreement to limit its remedy for Buyer's
default to termination of this Agreement is a material inducement to Buyer's
execution of this Agreement. Seller and Developer hereby waive, relinquish and
release any and all other rights and remedies for Buyer's default under this
Agreement, including, but not limited to: (1) any right to sue Buyer for
damages, or (2) any other right or remedy which Seller or Developer may
otherwise have against Buyer, either at law, or equity or otherwise. [

                  15.2     SELLER OR DEVELOPER DEFAULT. In the event that Seller
or Developer defaults in the observance or performance of a material covenant or
material obligation hereunder and the liability of such party for failing to
observe such covenant or obligation is not addressed or otherwise governed by
the terms of the Sale Development Agreement or by the terms of Sections 6 and 9
of this Agreement, and furthermore, such default continues for six (6)
consecutive calendar days after the date of receipt of written notice from Buyer
demanding cure of such default, or such longer period as may be reasonably
required to effect a cure (but in no event to exceed a total of ninety (90)
days), Buyer shall be entitled either, at Buyer's option, (i) if Buyer has
theretofore complied with Buyer's obligations under this Agreement, to sue
Seller or Developer, as appropriate, for specific performance of this Agreement,
or (ii) to terminate this Agreement and the Sale Development Agreement (except
to the extent that any right, obligation or liability set forth herein expressly
survives termination of this Agreement) by the delivery to Seller and Developer
of notice of such termination, which termination shall be effective


                                       35
<PAGE>   36

the fifth (5th) consecutive calendar day after the date of receipt of such
notice unless such default is earlier cured. In the event that Buyer has elected
to terminate this Agreement and the Sale Development Agreement, Buyer shall be
entitled to pursue a claim against Seller and Developer for Buyer's actual
damages (including without limitation, the increase in aggregate costs incurred
by Buyer under the Lease compared to Buyer's aggregate costs under this
Agreement) incurred as a result of such default, but otherwise excluding
consequential damages, not to exceed One Hundred Fifty Thousand and No/100
Dollars ($150,000.00). The foregoing shall be Buyer's sole remedies in the event
of Seller's or Developer's default under this Agreement, except as may be
provided in Section 16.1 hereof, and Seller and Developer shall not have any
further liability to Buyer for liquidated or actual damages or otherwise. The
parties acknowledge that the Property is unique because of its location and
because the Improvements have been custom designed for Buyer. Seller's and
Developer's failure to perform under this Agreement, including but not limited
to the conveyance of the Property to Buyer, would cause Buyer to suffer
irreparable harm, and such failure could not be remedied by the payment of
monetary damages. The parties accordingly agree that Buyer shall be entitled to
the remedy of specific performance for nonperformance of this Agreement by
Seller or Developer. Seller and Developer waive any right they might otherwise
have to object to the remedy of specific performance, and agree that they will
not assert that specific performance is not an available remedy.

         16.      GENERAL PROVISIONS.

                  16.1     TERMINATION If this Agreement is terminated or the
Property is otherwise not conveyed to Buyer under any circumstances, except
where Seller and Developer have complied with all of their obligations under
this Agreement and Buyer has defaulted under this Agreement, Seller shall pay to
Buyer the sum of One Hundred Fifty Thousand and No/100 Dollars ($150,000.00) on
or before the commencement date of the Lease (or on the due date of the next due
rental payment if the Lease has previously commenced). Seller's agreement to pay
such amount is a material inducement to Buyer's execution of this Agreement.

                  16.2     EXECUTION NECESSARY. This Agreement shall not be
binding upon Seller and Developer until fully executed and delivered by proper
officials of Seller and Developer, and no action taken by Seller's or
Developer's corporate executives shall be deemed an acceptance of this Agreement
until this Agreement has been so executed by Seller and Developer and delivered
to Buyer.

                  16.3     COUNTERPARTS. This Agreement may be executed in
separate counterparts. It shall be fully executed when each party whose
signature is required has signed at least one counterpart even though no one
counterpart contains the signatures of all of the parties to this Agreement.

                                       36
<PAGE>   37

                  16.4     SUCCESSORS AND ASSIGNS. Seller and Developer hereby
agree that Buyer may freely and unilaterally assign in its sole discretion,
without the need for cause to be given and without prior notice to or consent of
the Seller or Developer or any surety required, Buyer's duties, rights and
interests under this Agreement to any Buyer-affiliated entity or to an
owner-trustee pursuant to a synthetic lease financing entered into by Buyer or
its Affiliate for the Property. Neither the Seller's or Developer's obligations
hereunder nor the Seller's or Developer's right to receive payments under this
Agreement nor any other interest, right or duty of such party under this
Agreement may be assigned without the prior written consent of Buyer, which
consent may not be unreasonably withheld for any reason. Notwithstanding the
foregoing, in connection with the sale, transfer, assignment, conveyance or
other disposition of all or substantially all of the real property assets of
Developer or any of its subsidiaries (the "RE Assets"), Developer may assign,
with notice to Buyer but without Buyer's consent, its interest and obligations
under this Agreement, the Sale Development Agreement, and the Lease Development
Agreement, and may delegate or cause the assumption of its obligations and
responsibilities thereunder to the entity (the "Assignee") that acquires
(directly or indirectly through wholly-owned entities) the RE Assets, provided
that: (i) Assignee, at the time of such assignment or transfer, on a
consolidated basis with its wholly-owned entities, has (a) a total asset value
of at least $200,000,000.00 and (b) a net worth of at least $50,000,000.00; (ii)
W. Michael Doramus or Darryl A. LeClair are senior or executive management
personnel of Assignee at the time of such assignment or transfer; and (iii) such
Assignee assumes all of Seller's and Developer's obligations and
responsibilities under this Agreement, the Sale Development Agreement, and the
Lease Development Agreement. Upon such assignment or transfer, Seller and
Developer will be released from their respective liabilities under this
Agreement and the Sale Development Agreement. Developer may also delegate its
obligations under the Sale Development Agreement and the Lease Development
Agreement to a wholly-owned subsidiary of Developer or Assignee, but shall not
be released from liability thereunder due solely to such delegation. Seller may
assign its interest under this Agreement to Assignee or any wholly-owned
subsidiary of Assignee. Transfer of any membership interest in Seller shall not
violate this Section. This Agreement shall be binding upon and inure to the
benefit of the parties hereto and their respective successors and assigns.
Seller expressly acknowledges that, at Closing, Buyer may direct Seller to
transfer the Property to a synthetic lease owner-trustee, in which event Seller
acknowledges that the owner-trustee shall have no liability under this
Agreement.

                  16.5     ENTIRE AGREEMENT. This Agreement and the Sale
Development Agreement and all the exhibits referenced herein and annexed hereto
and thereto contain the entire agreement of the parties hereto with respect to
the matters contained therein, and no prior agreement or understanding
pertaining to any of the matters connected with this Transaction shall be
effective for any

                                       37
<PAGE>   38

purpose. Except as may be otherwise provided herein, the agreements embodied
herein may not be amended except by an agreement in writing signed by the
parties hereto.

                  16.6     TIME IS OF THE ESSENCE. Time is of the essence of
this Agreement. Anywhere a day certain is stated for payment or for performance
of any obligation, the day certain so stated enters into and becomes a part of
the consideration for this Agreement. If any date set forth in this Agreement
shall fall on, or any time period set forth in this Agreement shall expire on, a
day which is a Saturday, Sunday, federal or state holiday, or other non-business
day, such date shall automatically be extended to, and the expiration of such
time period shall automatically to be extended to, the next day which is not a
Saturday, Sunday, federal or state holiday or other non-business day. The final
day of any time period under this Agreement or any deadline under this Agreement
shall be the specified day or date, and shall include the period of time through
and including such specified day or date.

                  16.7     GOVERNING LAW. This Agreement shall be governed by
the laws of the state in which the Land is located.

                  16.8     SURVIVAL. All covenants, agreements, indemnities,
representations and warranties contained herein shall survive the Closing Date
for one (1) year and no longer (provided claims are asserted against Seller or
Developer within such one (1) year period), except for those covenants and
agreements which are actually performed at Closing and except as may be
otherwise specifically provided in this Agreement.

                  16.9     FURTHER ASSURANCES. Each party agrees to execute and
deliver to the other such further documents or instruments as may be reasonable
and necessary in furtherance of the performance of the terms, covenants and
conditions of the within Agreement. This covenant shall survive the Closing.

                  16.10    EXCLUSIVE APPLICATION. Nothing in this Agreement is
intended or shall be construed to confer upon or to give to any person, firm or
corporation other than Buyer and Seller hereto any right, remedy or claim under
or by reason of this Agreement. All terms and conditions of this Agreement shall
be for the sole and exclusive benefit of the parties hereto and may not be
assigned.

                  16.11    PARTIAL INVALIDITY. If all or any portion of any of
the provisions of this Agreement shall be declared invalid by laws applicable
thereto, then the performance of said offending provision shall be excused by
the parties hereto; provided, however, that, if the performance of such excused
provision materially affects any material aspect of this Transaction and if
either party does not upon demand from the other enter into a modification or
separate agreement which sets

                                       38
<PAGE>   39

forth in valid fashion the covenants of such offending provision, then the party
hereto for whose benefit such excused provision was inserted in this Agreement
shall have the right, exercisable by written notice given to the other party
within ten (10) days after such provision is so declared invalid, to terminate
this Agreement; thereupon this Agreement shall be null and void.

                  16.12    INTERPRETATION. The titles, captions and paragraph
headings are inserted for convenience only and are in no way intended to
interpret, define, limit or expand the scope or content of this Agreement or any
provision hereof. If any party to this Agreement is made up of more than one
person or entity, then all such persons and entities shall be included jointly
and severally, even though the defined term for such party is used in the
singular in this Agreement. If any time period under this Agreement ends on a
day other than a Business Day, then the time period shall be extended until the
next Business Day. This Agreement shall be construed without regard to any
presumption or other rule requiring construction against the party causing this
Agreement to be drafted. If any words or phrases in this Agreement shall have
been stricken out or otherwise eliminated, whether or not any other words or
phrases have been added, this Agreement shall be construed as if the words or
phrases so stricken out or otherwise eliminated were never included in this
Agreement and no implication or inference shall be drawn from the fact that said
words or phrases were so stricken out or otherwise eliminated.

                           A.       DEFINED TERMS. Capitalized terms used in
         this Agreement shall have the meanings ascribed to them at the point
         where first defined, irrespective of where their use occurs, with the
         same effect as if the definitions of such terms were set forth in full
         and at length every time such terms are used.

                           B.       PRONOUNS. Wherever appropriate in this
         Agreement, personal pronouns shall be deemed to include the other
         genders and the singular to include the plural.

                  16.13    WAIVER RIGHTS. Buyer reserves the right to waive, in
whole or in part, any provision hereof which is for the benefit of Buyer. Each
of Seller and Developer reserves the right to waive, in whole or in part, any
provision hereof which is for the benefit of such party.

                  16.14    NO IMPLIED WAIVER. Unless otherwise expressly
provided herein, no waiver by Seller or Buyer of any provision hereof shall be
deemed to have been made unless expressed in writing and signed by such party.
No delay or omission in the exercise of any right or remedy accruing to Seller,
Developer, or Buyer upon any breach under this Agreement shall impair such right
or remedy or be construed as a waiver of any such breach theretofore or
thereafter occurring. The waiver by Seller, Developer, or Buyer of any breach of
any term, covenant or


                                       39
<PAGE>   40

condition herein stated shall not be deemed to be a waiver of any other breach,
or of a subsequent breach of the same or any other term, covenant or condition
herein contained.

                  16.15    RIGHTS CUMULATIVE. All rights, powers, options or
remedies afforded to Seller, Developer, or Buyer either hereunder or by law
shall be cumulative and not alternative, and the exercise of one right, power,
option or remedy shall not bar other rights, powers, options or remedies allowed
herein or by law, unless expressly provided to the contrary herein. Without
limiting the generality of the foregoing, the provisions under this Agreement
and under the Sale Development Agreement shall be cumulative, except in the case
of irreconcilable inconsistency, in which case the provisions of the Development
Agreement shall govern. So long as both this Agreement and the Lease remain in
effect, the rights, powers, options or remedies afforded to Seller, Developer,
or Buyer under this Agreement and under the Lease shall be cumulative, except
that: (i) any damages (including liquidated damages) awarded to non-defaulting
party under this Agreement shall offset and be credited against the
non-defaulting party's claim for damages or liquidated damages for the same
breach or default under the Lease, and (ii) any damages (including liquidated
damages) awarded to non-defaulting party under the Lease shall offset and be
credited against the non-defaulting party's claim for damages or liquidated
damages for the same breach or default under this Agreement.

                  16.16    ATTORNEY'S FEES. Should either party employ an
attorney or attorneys to enforce any of the provisions hereof or to protect its
interest in any manner arising under this Agreement, or to recover damages for
breach of this Agreement, the non-prevailing party in any action pursued in
arbitration or in a court of competent jurisdiction (the finality of which is
not legally contested) agrees to pay to the prevailing party all reasonable
costs, damages and expenses, including reasonable attorney's fees actually
incurred, expended or incurred in connection therewith.

                  16.17    EXHIBITS AND SCHEDULES. All exhibits and schedules
referred to in, and attached to, this Agreement are hereby incorporated herein
in full by this reference.

                  16.18    CONFIDENTIALITY. Other than the Seller's and
Developer's disclosure to its lenders and bonding companies of the existence of
this Agreement and the value of the work-in-process and any other disclosures
made to third parties prior to the date of this Agreement, none of the parties
shall, without the prior written consent of the other parties, disclose or make
available to any person, or use, directly or indirectly, except for the
performance and implementation of the Project work, any confidential information
in connection with the Project, including this Agreement and the work
thereunder.



                                       40
<PAGE>   41

         As used herein, the term "confidential information" shall mean any
information, written or oral, concerning the Project, relating to or consisting
of processes, techniques, procedures, designs, drawings, plans, diagrams,
specifications, computer programs, systems, know-how, trade secrets and other
technical data, Project information, policies and contracts, including this
Agreement.

         Buyer, Seller, and Developer each further agree that it shall not make
any announcements or release any information or photographs concerning this
Agreement, or the Project or any part thereof, to any member of the public or
press or any official body, unless prior written consent is obtained from the
other parties.

         Each party shall take all steps which may be necessary or appropriate
in order that its respective officers, members, directors, agents, consultants
and employees and all subcontractors and suppliers, adhere to the provisions of
these conditions. Appropriate clauses to carry out the purpose and intent hereof
shall be included in all subcontracts, purchase orders and contracts entered
into by each party. Any material breach of this confidentiality provision shall
be an event of default upon which the non-defaulting party, in its sole
discretion, without notice and cure rights to Seller or Developer, may
immediately terminate this Agreement. This "confidential information" provision
shall survive termination of this Agreement.

                  16.19    FACSIMILE AS WRITING. The parties expressly
acknowledge and agree that, notwithstanding any statutory or decisional law to
the contrary, the printed product of a facsimile transmittal shall be deemed to
be "written" and a "writing" for all purposes of this Agreement, however,
facsimiles may not be used to provide any notice for this Agreement.

                            [EXECUTION PAGE FOLLOWS]


                                       41
<PAGE>   42


         IN WITNESS WHEREOF, Buyer, Seller, and Developer have executed this
Agreement under seal as of the day and year first above written.

                                          SELLER:

                                          200 CARILLON L.L.C.,
                                          a Delaware limited liability company

                                          By:
                                              Name:
                                              Title:


                                          DEVELOPER:

                                          ECHELON INTERNATIONAL CORPORATION,
                                          a Florida corporation

                                          By:
                                              Name:
                                              Title:


                                          BUYER:

                                          CATALINA MARKETING SALES
                                          CORPORATION, a Florida corporation


                                          By:
                                              Name:
                                              Title:



                                       42
<PAGE>   43





                      SCHEDULE 1.2: STANDARD DEFINED TERMS


                  (ATTACHED TO AND MADE A PART OF THAT CERTAIN
                   PURCHASE AND SALE AGREEMENT BY AND BETWEEN
                    ECHELON AT CARILLON TWO, INC., AS SELLER,
             ECHELON INTERNATIONAL CORPORATION, AS A DEVELOPER, AND
                    CATALINA MARKETING CORPORATION, AS BUYER,
                        DATED AS OF _____________, 1999)


         "AFFILIATE" shall mean: (a) as to Seller, (i) a corporation,
partnership, limited liability company, individual or other entity owned (in
whole or in part) or controlled by Seller or any of the officers, members or
partners of Seller, or (ii) a corporation, partnership, limited liability
company, individual or other entity owning or controlling, or under common
ownership or control with, Seller, or any of the officers, members or partners
of Seller, or otherwise affiliated with Seller or any of the officers, members
or partners of Seller; (b) as to Echelon International, (i) a corporation,
partnership, limited liability company, individual or other entity owned (in
whole or in part) or controlled by Echelon International or any of the officers,
members or partners of Echelon International, or (ii) a corporation,
partnership, limited liability company, individual or other entity owning or
controlling, or under common ownership or control with, Echelon International,
or any of the officers, members or partners of Echelon International, or
otherwise affiliated with Echelon International or any of the officers, members
or partners of Echelon International; (c) as to Assignee, (i) a corporation,
partnership, limited liability company, individual or other entity owned (in
whole or in part) or controlled by Assignee or any of the officers, members or
partners of Assignee, or (ii) a corporation, partnership, limited liability
company, individual or other entity owning or controlling, or under common
ownership or control with, Assignee, or any of the officers, members or partners
of Assignee, or otherwise affiliated with Assignee or any of the officers,
members or partners of Assignee; and (d) as to Buyer: (i) a corporation,
partnership, limited liability company, individual or other entity owned (in
whole or in part) or controlled by Buyer or any of the officers, members or
partners of Buyer, or (ii) a corporation, partnership, limited liability
company, individual or other entity owning or controlling, or under common
ownership or control with, Buyer or any of the officers, members or partners of
Buyer, or persons otherwise affiliated with Buyer or any of the officers,
members or partners of Buyer.

         "AGREEMENT" shall mean this Purchase And Sale Agreement between Seller,
Developer, and Buyer with respect to the Property.

         "BUSINESS DAY" shall mean Monday through Friday excluding holidays
recognized by the state government of the State in which the Property is
located.

                                       43

<PAGE>   44

         "BUILDING SYSTEMS" shall mean systems and facilities with respect to
the Property, including, but not limited to, elevators, security systems, HVAC,
utilities, telephone service (including any cellular or digital facilities),
Internet access, and common area amenities.

         "BUYER" shall mean the buyer referenced in the first paragraph of this
Agreement. This definition shall be subject to Buyer's right of assignment of
this Agreement, and right to require that title to the Improvements pass to an
Affiliate of Buyer or a financing owner-trustee at Closing.

         "CLAIM" has the meaning contained in Section 4.3 A hereof.

         "CLOSING" shall mean the consummation and closing of the Transaction.

         "CLOSING PRORATION TIME" shall mean (a) if the Purchase Price is
received by Seller for investment credit (or by the closing agent, along with
authorization from Buyer to release such proceeds) prior to 2:00 P.M. local
Tampa, Florida time on the Closing Date, as of 11:59 P.M. local Tampa, Florida
time on the day prior to the Closing Date, in which event the day of Closing
shall belong to Buyer, and (b) if the Purchase Price is received by Seller (or
by the closing agent as aforesaid) at or after 2:00 P.M. local Tampa, Florida
time on the Closing Date, 11:59 P.M. local Tampa, Florida time on the Closing
Date, in which event the day of Closing shall belong to Seller.

         "CONDEMNATION PROCEEDING" shall mean any proceeding in condemnation,
eminent domain or any written request for a conveyance in lieu thereof, or any
notice that such proceedings have been or will be commenced against any portion
of the Property.

         "DESIGN AND CONSTRUCTION CONTRACTS" shall mean all contracts between
Seller or Developer and any third party relative to the design, engineering,
construction, operation and/or maintenance of the Improvements on the Real
Property or related to the Personal Property, including, but not limited to the
contracts between Developer and the members of the Design and Construction Team.
"DESIGN AND CONSTRUCTION CONTRACTS" shall also include the contract between the
Base Building Contractor and the Base Building Architect.

         "DESIGN AND CONSTRUCTION TEAM" means the Base Building Architect, the
Base Building Contractor, and the Tenant Improvements Contractor (but shall
exclude the Tenant Improvement Architect).

         "DEVELOPER" shall mean the entities referenced in the first paragraph
of this Agreement. All obligations of Developer under this Agreement shall be
joint and several.

                                       44

<PAGE>   45

         "ECHELON INTERNATIONAL" has the meaning contained in the first
paragraph hereof.

         "EFFECTIVE DATE" shall mean the date on which the last to sign of
Seller, Developer, and Buyer executes this Agreement.

         "ENVIRONMENTAL MATTER" shall mean any matter related in any manner
whatsoever to (i) the disposal or release of solid, liquid or gaseous waste into
the environment, (ii) the treatment, storage or other handling of any Hazardous
Substance, (iii) the placement of structures or materials into waters of the
United States, or (iv) the presence of any Hazardous Substance in any building,
structure or workplace.

         "ENVIRONMENTAL LAWS" shall mean any applicable local, state or federal
law with respect to the release of Hazardous Substances, the regulation of the
discharge of solid, liquid or gaseous waste into the environment or the
placement of structures or materials into the waters of the United States,
including, without limitation, the Comprehensive Environmental Response,
Compensation and Liability Act of 1980, as amended ("CERCLA"), 42 U.S.C. ss.9601
et seq.; the Resource Conservation and Recovery Act, as amended ("RCRA") 42 USC
ss.6901 et seq.; the Hazardous MaterialS Transportation Act, as amended, 49
U.S.C. ss.1801, et seq.; the Federal Water Pollution Control Act, as amended, 33
U.S.C. ss.1251, et seq.; and any other applicable law or regulation.

         "ENVIRONMENTAL LITIGATION" shall mean any claims, actions, suits,
proceedings or investigations related to Environmental Matters pending or
threatened against Seller or any predecessors interest with respect to the
ownership, use, condition, or operation of the Property in any court or before
or by any federal, state or other governmental agency or private arbitration
tribunal.

         "GATEWAY" has the meaning contained in the Recitals hereto.

         "HAZARDOUS SUBSTANCE" shall mean any hazardous or toxic substance or
waste as those terms are defined by any applicable Environmental Law, together
with (if not so defined by such Environmental Laws), petroleum, petroleum
products, oil, PCBs and asbestos.

         "IMPROVEMENTS" shall mean the buildings, structures (surface and
subsurface), interior tenant improvements and other improvements and fixtures
now or hereafter situated on or attached to any parcel of the Land, which
Improvements shall consist of a five (5) story office building with
approximately 142,857 rentable square feet, constructed of a structured steel
frame with an architectural pre-cast concrete exterior, with interior tenant
improvements and surface and structural parking for approximately 670
automobiles (a ratio of

                                       45

<PAGE>   46

approximately 4.7 spaces per 1,000 rentable square feet), together with other
amenities and improvements, to be constructed and completed by Developer in
accordance with the terms of this Agreement and the Sale Development Agreement.

         "LAND" shall mean that certain tract or parcel of land, more
particularly described on EXHIBIT A.

         "LAND USE COMPLIANCE DOCUMENTS" has the meaning contained in Paragraph
[8.6K].

         "LAND USE REQUIREMENTS" shall mean all deed restrictions, restrictive
covenants, building codes, zoning restrictions and Environmental Laws, and any
other law, ordinance, covenant, restriction or regulation affecting the Real
Property or Improvements.

         "LEGAL REQUIREMENTS" has the meaning contained in Paragraph 4.2 A
hereof.

         "LIEN" shall mean any mortgage, deed of trust, security deed, lien,
judgment, pledge, conditional sales contract, security interest, past-due taxes,
past-due assessments, contractor's lien, materialmen's lien, judgment or similar
encumbrance against the Property of a monetary nature.

         "LIQUIDATED DAMAGE AMOUNT" shall have the meaning contained in Section
15.1 hereof.

         "LOSS" shall mean any and all direct or indirect demands, claims,
payments, obligations, actions or causes of action, assessments, losses,
liabilities, costs and expenses, including, without limitation, penalties,
interest on any amount payable to a third party as a result of the foregoing,
lost income and profits, and any legal or other expenses (including, without
limitation, reasonable attorneys' fees and expenses) reasonably and actually
incurred in connection with investigating or defending any claims or actions,
whether or not resulting in any liability.

         "OTHER INTERESTS" shall mean any other interests of Seller or Developer
in and to the Real Property and the Improvements or pertaining thereto,
including, without limitation, all of the right, title and interest of the
Seller or Developer in and to:

                  (i)      All Property Documents;

                  (ii)     All entitlements of the Seller or Developer in and to
         any award made or to be made in lieu of any of the interests to be
         conveyed hereunder, including any award or payment made or to be made
         (a) for any taking in any Condemnation Proceeding of land lying in the
         bed of any street, road,

                                      46
<PAGE>   47

         highway or avenue, open or proposed, in front of or adjoining all or
         any part of the Land, (b) for damage to the Property or any part
         thereof by reason of change of grade or closing of any such street,
         road, highway or avenue, and (c) for any taking in a Condemnation
         Proceeding of any part of the Property;

                  (iii)    Any name or trade name by which the Improvements or
         the Real Property or any part thereof may be known, if any, including,
         but not limited to the Project Name and all other fictitious names used
         on the date hereof in connection with the ownership and operation of
         the Property and all registrations for such names, but expressly
         excluding any rights to the use of the names "Echelon" or "Carillon" or
         the business or corporate name of Assignee;

                  (iv)     The right to the use of any telephone number located
         under the Project Name and the right to list telephone numbers under
         the Project Name;

                  (v)      The Base Building Design Documents and the copyrights
                           therein; and

                  (vi)     All permits.

         "PERMITS" shall mean all licenses, certificates (including certificates
of occupancy), consents, variances, waivers, authorizations, permits and similar
approvals required for the construction, ownership, operation or occupancy of
the Property by Buyer and issued by governmental authorities having jurisdiction
over the Property or by private parties or associations pursuant to any of the
Permitted Title Exceptions or otherwise in connection with any Land Use
Requirement.

         "PERMITTED TITLE EXCEPTIONS" shall mean the following:

                  (a)      All real estate taxes not yet due and payable as of
         the Closing Date. Seller shall pay any special assessments (to the
         extent payable in installments and due prior to Closing) in full prior
         to Closing;

                  (b)      Any existing utility easements serving only the Real
         Property and no other land;

                  (c)      The state of facts disclosed by the Survey updated
         August 19, 1999, prepared by Polaris Associates, Inc., Job No.
         001-2365, previously delivered to Buyer by Seller or Developer and
         disclosed by a current Survey of the Land obtained by Buyer, provided
         such state of facts does not, in Buyer's reasonable judgment,
         materially interfere with (i) the current use, or the use contemplated
         by Buyer as disclosed to Seller, of any portion of the Land or the
         Improvements, (ii) the performance of any covenant, obligation,


                                       47
<PAGE>   48

         representation or warranty of the owner of the Property under any
         Permitted Title Exceptions, (iii) the maintenance and operation of the
         Improvements or the continued use thereof for the same purposes as
         presently used, (d) the meeting of the normal requirements of a
         mortgage lender, or (e) Buyer's obtaining title insurance (including
         insurance of marketability) satisfactory to Buyer; and

                  (d)      All matters of record as reflected in the Title
         Commitment, and any other matters approved as Permitted Title
         Exceptions in writing by Buyer prior to Closing or deemed approved as
         Permitted Title Exceptions pursuant to this Agreement.

         "PERSONAL PROPERTY" shall mean all personal property owned by Seller or
Developer but only if used or usable in connection with any present or future
occupation or operation of all or any part of the Real Property or the
Improvements or both, together with (to the extent not constituting a portion of
the Real Property) all fixtures, furniture, furnishings, carpeting, draperies,
fittings, equipment, machinery, apparatus, building materials, appliances and
articles, whether located on or off the Real Property and used or usable in
connection with any present or future occupation or operation of all or any part
of the Real Property or the Improvements or both, including, without limitation,
all elevators, escalators, boilers, furnaces, heating, ventilating and
air-conditioning systems, office furnishings and equipment, building drawings,
plans and specifications, building materials and wall partitions, sprinkler and
well systems, sewerage systems, electrical equipment, fire prevention and
extinguishing apparatus, engineering, maintenance and supplies and materials,
fuel and other supplies of all kinds whether used, unused or in stock for future
use in connection with the maintenance and operation of the Property, which are
on hand on the date hereof, subject to such depletion and including such
resupplying as shall occur and be made in the normal course of business.

         "PLANS AND SPECIFICATIONS" shall mean the final plans and
specifications for construction of the Improvements, as prepared by the Base
Building Architect and the Tenant Improvements Architect, and all amendments and
supplements thereto, including site plans, elevation renderings and landscaping
plans, including full architectural and engineering review.

         "PROJECT" means the Improvements or the design, construction, and
completion thereof, as appropriate for the context in which such term is used.

         "PROPERTY" shall mean the Real Property, the Improvements, the Personal
Property and the Other Interests.

         "PROPERTY DOCUMENTS" has the meaning contained in Paragraph [9.1G]
hereof.

                                       48
<PAGE>   49

         "REAL PROPERTY" shall mean the Land, including, without limitation, (a)
any and all buildings located on the Land and all other Improvements, (b) all
easements appurtenant to the Land and other easements, grants of right,
licenses, privileges or other agreements for the benefit of, belonging to or
appurtenant to the Land whether or not situate upon the Land, all whether or not
specifically referenced on EXHIBIT A, (c) all mineral, oil and gas rights,
riparian rights, water rights, sewer rights and other utility rights allocated
to the Land, (d) all right, title and interest of the owner of the Land in and
to any roads, streets and ways, public or private, open or proposed, in front of
or adjoining all or any part of the Land and serving the Land, (e) all rights to
development of the Land granted by governmental entities having jurisdiction
over the Land, subject to the restrictions on development as provided on the
Deed.

         "SELLER" shall mean the seller referenced in the first paragraph of
this Agreement.

         "SELLER'S OR DEVELOPER'S KNOWLEDGE" shall mean (i) the actual knowledge
of the following individuals: Julio Maggi and Daryl LeClair (the "KNOWLEDGEABLE
PARTIES"), (ii) any written notice with respect to an item or condition
delivered to a Knowledgeable Party (but not including such notices delivered to
the predecessors of such Knowledgeable Parties in their respective positions
with Seller or Developer or any notices delivered to the Knowledgeable Parties
as a transfer of files and other data upon their assumption of responsibility
with respect to the Property), or (iii) any oral communication by any third
party with a Knowledgeable Party.

         "SURVEY" shall mean a current as-built plat of survey of the Land
prepared for and certified by Polaris, Inc. or other registered land surveyor
licensed as such in the state in which the Property is located. The Survey (a)
shall be prepared for and certified by a registered land surveyor licensed as
such in the State in which the Property is located, (b) sufficiently current so
as to permit deletion of the standard survey exception on the Title Policy, (c)
shall be coordinated with Buyer's title examination (and shall show the location
of all easements and other encumbrances referenced therein), and (d) shall
comply with the Florida Minimum Technical Standards. The Survey shall show the
following items, whether covered by the foregoing minimum detail requirements or
not:

                  (i)      All courses and distances referred to in the
         description of the Land.

                  (ii)     The location of all Improvements on the Land with the
         dimensions thereof. If deed restrictions, recorded plats or zoning
         ordinances require a building to be set back specified distances from
         street or property lines, the Survey must show measured distances from
         said building to said lines. The Survey must contain a certification
         from the Surveyor that the

                                       49
<PAGE>   50

         Improvements and any other items on the Land do not encroach over any
         boundary line of the Land, any set-back or buffer line or any easement
         boundary; any exceptions to this certification must be set forth in the
         certification and are subject to Buyer's approval in Buyer's sole
         discretion.

                  (iii)    Location of all record exceptions and any other
         visible easements, rights-of-way, water courses, drains, sewers,
         encroachments, driveways or roads which serve the Land and to which the
         Land is subject (excluding any easements not located on the Property
         which are uniform to and run throughout all of plat of Carillon Park),
         including references to the recording data of the instruments creating
         such easements, rights-of-way, drains, sewers, courses, driveways or
         roads, if such instruments are recorded.

                  (iv)     The names and widths of the rights-of-way of streets
         adjacent to or serving the Land with the distance from the nearest
         corner to the beginning point of the Land surveyed; the extent and
         location of any limitation of access or development, together with a
         reference to the instrument limiting such access, and the extent and
         location of any permitted access points within any limited access area,
         together with a reference to the permit or other instrument permitting
         such access.

                  (v)      The total acreage or square foot area of the Land.

                  (vii)    The boundary lines of each portion of the Land
         encumbered by any recorded lease, if applicable.

                  (viii)   Interior lines and facts sufficient to insure full
         contiguity of each parcel if the Land is composed of more than one
         parcel, together with the surveyor's certification of such contiguity.

                  (ix)     The surveyor shall note the applicable flood zone
         classification in the surveyor's certification.

                  (ix)     The political subdivision and county in which the
         Land is located and such other notations as will accurately describe
         and depict the location of the Land surveyed.

The Survey and the surveyor's certifications should be addressed to Buyer,
Seller and the Title Company. The Survey must be dated as of the date the Survey
was made on the ground, signed and sealed by the surveyor and certified (or
re-certified) by the surveyor that the Survey was actually made on the ground
and is correct.

         "TITLE COMMITMENT" shall mean the commitment of the Title Company to
issue the Title Policy.

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<PAGE>   51

         "TITLE POLICY" shall mean the full coverage, revised ALTA 1992 form
title policy with Florida modifications issued by the Title Company in the
amount of the Purchase Price, and containing, unless prohibited by applicable
statutes or regulations, the following endorsements: (a) "same land as survey"
(Survey legal matches title legal); and (b) such other endorsements as are
reasonably required by Buyer. The Title Policy shall insure as separate insured
parcels any easement rights running to the benefit of the Property, including,
without limitation, easements for storm and sewer lines, storm drainage and
detention, and other utilities which are required in connection with the
operation of the Property.

         "TRANSACTION" shall mean the purchase and sale transaction contemplated
by this Agreement.

         "UCC SEARCHES" shall mean Uniform Commercial Code and other relevant
searches from the State and County in which the Land is located, and in which
the Seller or Developer maintains its chief executive office or its principal
business office, which shall show that there exist no UCC financing statements
or other Liens against Seller or Developer or with respect to the Property,
except the Permitted Title Exceptions.

         "WARRANTIES" shall mean each and every now existing and outstanding
bond and warranty concerning the Real Property, the Improvements located thereon
or the Personal Property, including, but not limited to, any and all bonds and
warranties, if any, now or hereafter in effect, arising out of, made, given or
issued, whether express or implied, in conjunction with any construction
contracts and any other contracts between Seller or Developer (or any
predecessors in title thereto) and any third party relative to the construction,
operation and/or maintenance of the Improvements on the Real Property or related
to the Personal Property, or otherwise arising out of, made, given or issued by
any such third party under each of the construction contracts (or by a
subcontractor performing any of the work which inures to the benefit of Seller
or Developer), all in conjunction with the construction, operation and/or
maintenance of the Improvements made pursuant to the construction contracts, or
arising out of, made, given or issued, by manufacturers or suppliers, in
conjunction with the Improvements or the Personal Property, together with all
claims in contract or quasi-contract and any similar chose-in-action arising out
of or resulting therefrom; the Warranties shall include, without limitation, any
roofing, air conditioning, heating, elevator or other bond or warranty relating
to construction of the Improvements, subject to any applicable express
limitations contained in each such bond or warranty.

         "WARRANTY ESTOPPEL" has the meaning contained in Paragraph [8.6D].




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