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                                                                   EXHIBIT 10.26
FIRST AMENDMENT TO COMMERCIAL LEASE

         This First Amendment to Commercial Lease (this "Amendment") is made and
entered into as of December 13, 1999, by and between ACLP University Park SA II,
L.P., a Texas limited partnership ("Lessor"), and Globalscape, Inc., a Texas
corporation ("Lessee") for the purposes more fully described below.

                               R E C I T A L S:
                               ---------------

         A.  Lessor and Lessee are parties to that certain Commercial Lease (the
"Lease") dated as of April 13, 1999, wherein Lessor leased to Lessee the
Premises, as defined in the Lease;

         B.  Lessee and Lessor desire to amend the Lease as provided herein.

                              A G R E E M E N T:
                              -----------------

         NOW THEREFORE, in consideration of the mutual covenants and agreements
herein contained and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Lessor and Lessee hereby amend the
Lease and Lessor and Lessee agree as follows:

         8.  Termination of Right of First Refusal Lessor and Lessee agree that
             -------------------------------------
             Section 1.07, Leasing Term Limitation on Adjacent Space and Right
             of First Refusal, of the Lease, is hereby terminated and deleted in
             its entirety and that Lessee has no further rights or claim to any
             space in the Building other than the Leased Premises.

         9.  Leased Premises Lessee will take the Initial Space of 7,350 square
             ---------------
             feet and the Must Take Space of 7,350 square feet upon the
             Commencement Date of the Lease. The Leased Premises will comprise
             14,700 total rentable square feet upon the Commencement Date.

         10. Base Rent Section 1.04, Base Rent, Security Deposit, of the Lease
             ---------
             is hereby deleted and replaced in its entirety with the following:

             "1.04 Base Rent, Security Deposit. Base Rent is $15,888.25 net per
             month based upon an assumed 14,700 rentable square footage in the
             Leased Premises and shall be adjusted by $12.97 per rentable square
             foot per year based on the recalculation under Section 1.02 above.
             Security Deposit is $7,974.13."

         11. Improvement Allowance Tenant Improvement Allowance is hereby
             ---------------------
             increased from $22.00 per rentable square foot to $28.00 per
             rentable square foot.

         12. Amortization of Excess Improvement Allowance.
             --------------------------------------------

             (A)   Lessor has increased Lessee's Improvement Allowance and, as a
                   result, hereby deletes in its entirety the third to last
                   sentence in Section 6.01(A) which reads, "Lessee shall be
                   responsible for payment in advance of all work and
                   construction resulting from changes in the Lessee
                   Improvements Final Plans and Specifications requested by
                   Lessee if the additional cost attributable to the changes
                   exceed the Improvement Allowance by more than $3.00 as
                   described in subparagraph (c) below." and replaces it with
                   the following:

                         "Lessee shall be solely responsible for payment in
                         advance of all work and construction resulting from
                         changes in the Lessee Improvements which exceed the
                         Improvement Allowance."
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              (B)  The last two sentences of Section 6.01(C) are hereby
                   deleted in their entirety.

         13.  Miscellaneous
              -------------

              a.   Capitalized Terms. Terms not otherwise defined herein shall
                   -----------------
                   have the meanings ascribed thereto in the Lease.

              b.   Effect of Amendment. Except to the extent the Lease is
                   -------------------
                   modified by this Amendment, the remaining terms and
                   provisions of the Lease shall remain unmodified and in full
                   force and effect. In the event of a conflict between the
                   terms of the Lease and the terms of this Amendment, the terms
                   of this Amendment shall prevail.

              c.   Entire Agreement. This Amendment, together with the Lease,
                   ----------------
                   embodies this entire understanding between Lessor and Lessee
                   with respect to its subject matter and can be changed only by
                   an instrument in writing signed by Lessor and Lessee.

              d.   Counterparts. This Amendment may be executed in counterparts,
                   ------------
                   each of which shall be deemed an original, but all of which,
                   together, shall constitute one and the same Amendment.

         IN WITNESS WHEREOF, the parties have executed this Amendment as of the
date and year first set forth above.

LESSOR:                                      LESSEE:

ACLP UNIVERSITY PARK SA II, L.P.,            GLOBALSCAPE, INC.,
a Texas limited partnership                  a Texas corporation

By:  ACLP University Park SA II, L.P.,
     a Texas corporation,
     its general partner                     By: ___________________________
                                                 Name ______________________
                                                 Title: ____________________
     By: ________________________
         Sue Shelton
         Executive Vice President<PAGE>

                                                                   Exhibit 10.28
KAWA Consultores, S.A. de C.V.
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         CONTRACT AGREEMENT FOR TELECOMMUNICATIONS
                           CONSULTING SERVICES

This contract for Telecommunications Consulting Services is made between KAWA
Consultores of Mexico, D.F. (hereinafter referred to as KAWA) and American
Telesource Inc. (hereinafter referred to as ATSI) of San Antonio, Texas.

1)   Background.

     1.1)  KAWA Consultores is a corporation dully incorporated according to the
           laws of Mexico as established in Notary Public Statement N. 9318
           dated May 8th, 1996. KAWA wishes to provide specialized consulting
           services to ATSI.
     1.2)  American Telesource Inc. (ATSI) is also a corporation
           ---------------------------------------------------------------------
           ATSI wishes to receive specialized consulting services provided by
           KAWA.

2)   Articles.

Article ONE.- Starting date.
-----------
This contract shall become effective on January 1st, 1998 and remain valid for
twelve consecutive months. It can be extended for additional periods by written
notification from ATSI to KAWA.

Article TWO.- Focus and purpose of consulting activity.
-----------
Assist ATSI in developing and implementing the necessary relations in the
Central and Southamerican regions as a business relations base to expand ATSI's
Network coverage to the Americas.

Article THREE.- Description of the Service.
-------------
The consulting services to be provided by KAWA will focus on corporate relations
and business development and these activities will be defined according to the
following criteria :
 .   Collaborating in the development of ATSI's strategy in Mexico and Latin
    America.
 .   Developing high level business relationships and assisting on finding
    "country or regional" partners to expand the ATSI Network in Central and
    Southamerica.
 .   Exploring new business segments and opportunities in Central and
    Southamerica.
 .   Lobbying the regulatory authorities in Central and Southamerica for the
    necessary support.
 .   Identifying and evaluating acquisition and or alliance opportunities in the
    Central - american region.

Article FOUR. - Obligations.
------------

     By KAWA:
     -------
     1.1)   Pursue negotiations and reach corporate agreements and contracts
            with regional or country associates to establish and implement
            partnership and operative interconnection throughout Central and
            Southamerica.
     1.2)   KAWA shall make the best efforts to assure that the "country
            partner" in every case will be the most adequate and reliable option
            in the country and will pursue the relationship through to its
            completion.
     1.3)   KAWA shall dedicate an average of 90 hours per month of effective
            activity in order to expedite the deployment of the Network backbone
            for the Americas.
     1.4)   KAWA shall make intensive follow up and negotiations with
            representatives of Telecomm and of the corresponding officials in
            the Telecommunications Authorities in Latin American countries.
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     1.5)   KAWA shall dedicate travel time as required to pursue negotiations
            with potential partners and Telecomm officials in the Latin -
            american countries. For this purpose a period of 5 travel days per
            month shall be made available to ATSI as a minimum.
     1.6)   KAWA shall participate in the successful implementation and follow
            up of partnerships in each country in order to develop the market as
            required.

     By ATSI:
     -------
     2.1)   ATSI shall continue enhancing corporate support as required in order
            to follow up on the successful implementation of operations with
            each country or region including negotiations for equipment
            provisioning and Interconnection Agreements with "Regional or
            country" partners.
     2.2)   ATSI shall selectively provide assistance with a corporate
            representative when visiting countries or seeking country partners
            when this is required. This will include facilitating relationships
            with existing or potential partners and regulatory authorities with
            whom ATSI already has contacts.
     2.3)   ATSI shall increase local support with the US Carriers and customers
            in order to successfully implement products and services included in
            the Interconnection Contracts and Agreements.

Article FIVE. - Compensation.
------------

The basis for compensation is as follows :
a)   90 hours per month at $100 DLLs. or 9,000 DLLs. per month paid in cash.
b)   ATSI agrees to share 50 % of the corporate office expense including :
          .  Maintenance of the spaces.
          .  Conservation of furniture and office equipment.
          .  Assistant and office boy salaries.
          .  Light and telecommunications and other operative expenses.
These expenses have been estimated at $ 1,000 DLLs/month for the year of 1998
which shall be added to the compensation stated in point a) above.
c)   Travel and entertainment expenses. ATSI agrees to reimburse expenses
     according to the expense reports provided by KAWA.

Article SIX. - Form of payment.
-----------
The compensation shall be invoiced and paid in the US according to the
instructions provided by KAWA.

Article SEVEN. -Taxes and other expenses.
-------------
KAWA will be solely responsible for the payment of its taxes or other operating
expenses related with the consulting services except those specifically agreed
upon according with article THREE above.

Article EIGHT. - Termination.
-------------
This agreement could be terminated if the following occur:
a)  If at the end of twelve months ATSI does not wish to continue receiving the
    services of KAWA.
b)  Non compliance of the parties with the articles of this contract.
c)  Non compliance by ATSI of the committed compensation as per article THREE
    above.
d)  Regardless of the reason for the termination of this agreement KAWA will not
    reimburse any amount to ATSI.
e)  In case of anticipated termination prior to January 1st, 1999, ATSI agrees
    to pay an extraordinary compensation equivalent to 1 month of services
    according to article FIVE above.
f)  In case of anticipated termination caused by KAWA, KAWA agrees to notify
    of its intention with a minimum anticipation of 60 days.

Article NINE. - Contingencies.
------------
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Extraordinary events beyond the control of ATSI such as fire, explosion, major
earthquake, vandalism or similar shall not be considered as anticipated
termination. The affected party shall notify the other as soon as possible. In
this case non of the parties shall be liable to any penalty whatsoever.

Article TEN. - Confidentiality and non disclosure.
-----------
Both parties agree to treat all information and data regarding the consulting
services with full confidentiality and therefor agree to disclosure only by
written consent of the other party.

Article ELEVEN. - Jurisdiction.
--------------
For interpretation and arbitration of this agreement both parties agree to
submit to the laws and jurisdiction of Mexico City.

This agreement is signed in Mexico City on the 1st of January of 1998.

         For ATSI                                    For KAWA

         Mr. Arturo Smith                            Mr. Carlos Kauachi
         Chairman & CEO                              President

         /s/ Arturo Smith                            /s/ Carlos Kauachi
         ----------------                            ------------------

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