<PAGE>
 
                                                                   EXHIBIT 10.25


                           ASSET PURCHASE AGREEMENT

                                by and between

                             VDC CORPORATION LTD.

                                   as Buyer,

                                      and

                            PORTACOM WIRELESS, INC.

                                   as Seller



                                March 23, 1998
<PAGE>
 
                           ASSET PURCHASE AGREEMENT
                           ------------------------

     This ASSET PURCHASE AGREEMENT (the "Agreement") is made as of the 23rd day
of March, 1998, by and between VDC CORPORATION LTD., a Bermuda corporation
("Buyer"), and PORTACOM WIRELESS, INC., a Delaware corporation ("Seller").

                                  WITNESSETH:

     WHEREAS, Seller desires to sell, and Buyer desires to purchase, on the
terms and conditions hereafter set forth, certain of the assets of Seller as
described herein; and

     WHEREAS, Seller and Buyer are parties to that certain Asset Purchase
Agreement, dated as of November 25, 1997, as amended as of February 16, 1998,
concerning the subject matter hereof (the "Original Agreement"); and

     WHEREAS, Seller and Buyer intend that this Agreement supersede in its
entirety the Original Agreement; and

     WHEREAS, on March 23, 1998, Seller filed a voluntary petition for relief
under Chapter 11 of Title 11 of the United States Code (the "Bankruptcy Code")
before the United States Bankruptcy Court for the District of Delaware (or any
other tribunal exercising jurisdiction over the Debtor and property of its
estate, the "Court"); and

     WHEREAS, Seller remains in possession of its property and in control of its
business pursuant to (S)(S) 1107 and 1108 of the Bankruptcy Code; and

     WHEREAS, Seller and Buyer are parties to a Loan Agreement, Security
Agreement and Pledge Agreement, entered into on November 10, 1997, whereby Buyer
extended to Seller prior to the commencement of the case the principal sum of
approximately $360,000 (together with all accrued interests, costs and fees, the
"Pre-Petition Indebtedness"); and

     WHEREAS, Seller and Buyer are parties to a Debtor In Possession Loan,
Security and Pledge Agreement, entered into after the commencement of the case,
and subject to Court approval, whereby Buyer agreed to advance to Seller the
principal amount up to an additional $333,000, subject to the terms and
conditions set forth therein (together with all accrued interests, costs and
fees, the "Post-Petition Indebtedness" and together with the Pre-Petition
Indebtedness, the "Indebtedness"); and

     WHEREAS, Seller and Buyer agree that the transactions contemplated hereby
are other than in the ordinary course of Seller's business, and accordingly
Court approval is required; and

                                       1
<PAGE>
 
     WHEREAS, Seller and Buyer desire to consummate the transactions
contemplated hereby as quickly as possible in order to maximize the benefit to
the estate and intend to seek expedited consideration by the Court of the
approval of this Agreement; and

     NOW, THEREFORE, in consideration of the foregoing and the mutual covenants,
agreements and representations and warranties herein contained, and for other
good and legal consideration, the receipt and sufficiency of which is hereby
acknowledged, Seller and Buyer, intending to be legally bound hereby, agree as
follows:

                                   ARTICLE 1

                                  DEFINITIONS

     1.1  When used in this Agreement, the following terms, in their singular
and plural forms, shall have the meanings assigned to them below:

          "Act" means the Securities Act of 1933, as amended.
           ---                                               

          "Agreement" is defined in the initial paragraph hereof.
           ---------                                             

          "Assets" means all of Seller's right, title and interest in and to all
           ------                                                               
of the following described holdings:

          (i)  Two million shares of common stock, par value $.0l per share
("MAC Common Stock"), of Metromedia Asia Corporation ("MAC"), as evidenced by
Stock Certificate Number 59, dated February 28, 1997; and

          (ii) Warrants ("MAC Warrants") to purchase four million shares of
common stock, par value $.0l per share, at $4.00 per share, of MAC, as evidenced
by Warrant Number 19.

          "Buyer" is defined in the initial paragraph hereof.
           -----                                             

          "Cash Funds" is defined in Section 3.2(a).
           ----------                -------------- 

          "Claim" means a claim or demand for any and all Liabilities, damages,
           -----                                                               
losses, obligations, deficiencies, encumbrances, penalties, costs and expenses,
including reasonable attorneys' fees, resulting from, related to or arising out
of (i) any misrepresentation, breach of warranty or non-fulfillment of any
covenant of Seller set forth in this Agreement or in any Related Document; (ii)
Seller's ownership of the Assets; (iii) any and all actions, suits,
investigations, proceedings, demands, assessments, audits, judgments and claims
arising out of any of the foregoing.

          "Closing" and "Closing Date" are defined in Section 6.1.
           -------       ------------                 ----------- 

                                       2
<PAGE>
 
          "Disclosure Schedule" is defined in Section 4.1.
           -------------------                ----------- 

          "GAAP" means generally accepted accounting principles in the United
           ----                                                              
States, consistently applied.

          "Governmental Authority" means any foreign, federal, state, regional
           ----------------------                                             
or local authority, agency, body, court or instrumentality, regulatory or
otherwise, which, in whole or in part, was formed by or operates under the
auspices of any foreign, federal, state, regional or local government.

          "Indemnified Party" is defined in Section 10.4.
           -----------------                ------------ 

          "Indemnifying Party" is defined in Section 10.4.
           ------------------                ------------ 

          "Law" means any common law and any federal, state, regional, local or
           ---                                                                 
foreign law, rule, statute, ordinance, rule, order or regulation.

          "Liabilities" means liabilities, obligations, claims or debts of
           -----------                                                    
Seller of any type or nature, whether matured, unmatured, contingent or unknown,
including, without limitation, tort, contract or other claims asserted against
Seller which are based on acts or omissions occurring on, before or after the
Closing Date.

          "Lien" means any lien, charge, covenant, condition, easement, adverse
           ----                                                                
claim, demand, encumbrance, security interest, option, pledge, or any other
title defect, easement or restriction of any kind.

          "Purchase Price" is defined in Section 3.1.
           --------------                ----------- 

          "Registration Statement" is defined in Section 7.6.
           ----------------------                ----------- 

          "Related Documents" means this Agreement and each document or
           -----------------                                           
instrument executed in connection with the consummation of the transactions
contemplated herein.

          "Seller" is defined in the initial paragraph of this Agreement.
           ------                                                        

          "Termination Agreement" means that certain Termination Agreement,
           ---------------------                                           
dated September 11, 1996, by and among Seller, MAC, as successor-in-interest to
Asian American Telecommunications Corporation and Max E. Bobbitt, as Agent.

          "VDC Shares" is defined in Section 3.2(b).
           ----------                -------------- 

                                       3
<PAGE>
 
                                   ARTICLE 2

                          SALE AND PURCHASE OF ASSETS

     2.1  Agreement to Sell and Purchase Assets.  Subject to the terms and
          -------------------------------------                           
conditions hereof and on the basis of and in reliance upon the covenants,
agreements and representations and warranties set forth herein, on the Closing
Date Seller shall sell the Assets to Buyer, and Buyer shall purchase the Assets
from Seller.  The Assets shall be sold, transferred and conveyed by Seller to
Buyer free and clear of any and all claims, liens, encumbrances and the rights
of others.

     2.2  Responsibility for Liabilities.  Buyer shall not assume any
          ------------------------------                             
Liabilities of Seller by virtue of this Agreement or otherwise.  Notwithstanding
anything herein, in the Original Agreement or in any Related Document to the
contrary, except as otherwise expressly provided herein, Buyer is neither
assuming nor agreeing to pay or discharge any of the claims against, or
liabilities or obligations of, the Seller, Seller's bankruptcy estate or of any
other party and nothing in this Agreement shall be construed to the contrary.
All claims against, and liabilities and obligations of Seller, and Seller's
bankruptcy estate, whether known or unknown, suspected or unsuspected, direct or
contingent, in litigation, threatened or not yet asserted or existing with
respect to any aspect of the Assets, Seller's bankruptcy case or estate, or this
Agreement, arising or existing prior to or on the Closing Date are and shall
remain the responsibility of Seller and Seller's bankruptcy estate, and such
liabilities or obligations arising after Closing shall be the responsibility of
the Buyer.  The Order entered by the Court approving this Agreement shall
specifically provide that the Buyer is not liable for pre-Closing claims,
liabilities or obligations and is not liable as a successor-in-interest to
creditors of Seller or Seller's bankruptcy estate.

                                   ARTICLE 3

                         PAYMENT OF THE PURCHASE PRICE

     3.1  Purchase Price.  The purchase price ("Purchase Price") for the Assets
          --------------                                                       
shall consist of (i) the Closing Purchase Price (as such term is defined in
Section 3.2 below) and (ii) the Deferred Purchase Price (as such term is defined
in Section 3.5 below), if any.

     3.2  Closing Purchase Price.  The Closing Purchase Price (the "Closing
          ----------------------                                           
Purchase Price") shall be paid or delivered by Buyer at Closing in the following
manner:

          (a) Subject to adjustment pursuant to Section 3.4 hereof, Buyer shall
deliver an amount not to exceed the difference between Seven Hundred Thousand
Dollars ($700,000) and the outstanding Indebtedness (the "Cash Funds") in
immediately available funds in the form of cash, cashier's check or wire
transfer, and

                                       4
<PAGE>
 
          (b) Buyer shall deliver 5,300,000 shares of newly issued shares of
common stock, par value $2.00 per share, of Buyer (the "VDC Shares") in
accordance with the provisions of Section 3.3; and

          (c) Buyer shall satisfy of the Indebtedness.

     3.3  Allocation of Closing Purchase Price.  The Closing Purchase Price
          ------------------------------------                             
shall be allocated in the following manner:

          (a) At the Closing, Seller will deliver a schedule (the "Debt
Schedule") identifying its indebtedness as of the Closing Date.  Buyer shall
deliver to and deposit with Seller that portion of the Cash Funds and the VDC
Shares necessary to satisfy Seller's indebtedness to its creditors in the
amounts and manner as set forth in the Debt Schedule.  The Cash Funds and/or any
and all VDC Shares delivered to Seller pursuant to this Section 3.3(a) shall be
credited against and considered a part of the Closing Purchase Price and shall
be held and distributed by Seller to the creditors (or provision shall be made
for the ultimate distribution of such amounts and/or Shares to creditors upon
the final resolution of any disputed amounts payable or claims against Seller)
in accordance with the provisions of a further order of the Court.

          (b) Seller shall retain the VDC Shares until such time as a
disposition of such shares occurs to Seller's stockholders pursuant to a
confirmed plan of reorganization providing for the issuance of the VDC Shares
pursuant to the exemption set forth in Bankruptcy Code (S) 1 145, or an
effective registration statement in accordance with the provisions of Section
7.6 hereof

     3.4  Adjustment to Closing Purchase Price.  Forgiveness of the Indebtedness
          ------------------------------------                                  
shall constitute initial payments and deposits against the Closing Purchase
Price, and, as such, shall be applied towards the Closing Purchase Price under
this Agreement upon the Closing Date.

     3.5  Deferred Purchase Price.
          ----------------------- 

          (a) For the purposes of this Section 3.5, the terms listed below shall
have the following meanings:

              (i)  "MAC Base Price" means $12.00 per share for each share of MAC
common stock;

              (ii) "MAC Market Price" means

                   (A) If MAC's common stock is traded in the over-the-counter
market and not on any national securities exchange or in the NASDAQ Reporting
System, the market price shall be the average of the mean between the last bid
and ask prices per share, as reported by the National Quotation Bureau, Inc. or
an equivalent generally accepted reporting service, for the consecutive 20
trading days following the one year anniversary of the Closing Date,

                                       5
<PAGE>
 
or if not so reported, the average of the closing bid and asked prices for a
share of MAC common stock for the consecutive 20 trading days following the one
year anniversary of the Closing Date as furnished to MAC by any member of the
National Association of Securities Dealers, Inc., selected by MAC for that
purpose.

                   (B) If MAC's common stock is traded on a national securities
exchange or in the NASDAQ Reporting System, the market price shall be the simple
average of the closing prices of a share of MAC's common stock, as quoted on the
NASDAQ Reporting System or its other principal exchange for the consecutive 20
trading days following the one year anniversary of the Closing Date.

                   (C) If the market price cannot be determined for MAC's common
stock on such date on either of the foregoing bases, the market price shall be
the fair market value as reasonably determined by an investment banking firm
selected by Seller and Buyer, with the cost therefor to be home equally by
Seller and Buyer.

             (iii) "VDC Base Price" means $5.00 per share for each share of VDC
common stock; and

             (iv)  "VDC Market Price" means

                   (A) If VDC's common stock is traded in the over-the-counter
market and not on any national securities exchange nor in the NASDAQ Reporting
System, the market price shall be the average of the mean between the last bid
and ask prices per share, as reported by the National Quotation Bureau, Inc. or
an equivalent generally accepted reporting service, for the consecutive 20
trading days following the one year anniversary of the Closing Date, or if not
so reported, the average of the closing bid and asked prices for a share of VDC
common stock for the consecutive 20 trading days following the one year
anniversary of the Closing Date as furnished to VDC by any member of the
National Association of Securities Dealers, Inc., selected by VDC for that
purpose.

                   (B) If VDC's common stock is traded on a national securities
exchange or in the NASDAQ Reporting System, the market price shall be the simple
average of the closing prices at which a share of VDC's common stock traded, as
quoted on the NASDAQ Reporting System or its other principal exchange for the
consecutive 20 trading days following the one year anniversary of the Closing
Date.

                   (C) If the market price cannot be determined for VDC's common
stock on such date on either of the foregoing bases, the market price shall be
the fair market value as reasonably determined by an investment banking firm
selected by Seller and Buyer, with the cost therefor to be borne equally by
Seller and Buyer.

                                       6
<PAGE>
 
          (b) In the event that on the one year anniversary of the Closing Date,
MAC is a publicly held company whose shares are registered with the Securities
and Exchange Commission ("SEC") under the Securities Exchange Act of 1934, Buyer
shall pay and deliver to Seller the Deferred Purchase Price (the "Deferred
Purchase Price") calculated in accordance with Section 3.5(c) below, if any,
within ninety (90) days following the one year anniversary of the Closing Date.
The Deferred Purchase Price shall be paid, at VDC's sole option, in either (i)
immediately available funds in the form of cash, cashier's check or wire
transfer, or (ii) shares of VDC common stock.  In the event that VDC elects to
pay the Deferred Purchase Price in the form of shares of VDC common stock, such
stock shall be priced at the higher of $5.00 per share or the VDC Market Price
per share.

          (c) The Deferred Purchase Price shall be calculated in accordance with
the following formula:

               MAC Market Price - VDC Market Price x $5,000,000
               ----------------   ----------------
               MAC Base Price       VDC Base Price

          For example, assuming that the MAC Market Price is $13.20, and the VDC
Market Price is $5.00, the Deferred Purchase Price would equal (10% - 0%) x
($5,000,000) = $500,000.

          If the number calculated from the above formula is negative, there is
no Deferred Purchase Price.

                                   ARTICLE 4

                   REPRESENTATIONS AND WARRANTIES OF SELLER

     Seller represents and warrants to Buyer as follows:

     4.1  Disclosure Schedule.  Seller has delivered or caused to be delivered
          -------------------                                                 
to Buyer, prior to the execution of this Agreement, disclosure schedules, and
documents relating thereto, which include the numbered schedules specifically
referred to in this Agreement and which are attached hereto (collectively, the
"Disclosure Schedule").  To the best of Seller's knowledge, the information
contained in the Disclosure Schedule is complete and accurate in all material
respects and all documents that are attached to the Disclosure Schedule are
complete and accurate copies of the genuine original documents they purport to
represent as in effect on the date hereof Capitalized terms used in the
Disclosure Schedule and not otherwise defined therein have the meanings ascribed
to such terms in this Agreement.

     4.2  Organization and Standing of Seller.  Seller is a corporation duly
          -----------------------------------                               
organized, validly existing and in good standing under the laws of the State of
Delaware.  Subject only to approval by the Court, Seller has all requisite
corporate power and authority to sell the Assets, free and clear of any and all
Liens.  A certified copy of Seller's Articles of Incorporation and Bylaws are
attached to Schedule 4.2 of the Disclosure Schedule.
            ------------                            

                                       7
<PAGE>
 
     4.3  Encumbrances Created by this Agreement.  The execution and delivery of
          --------------------------------------                                
this Agreement and each of the Related Documents does not, and the consummation
of the transactions contemplated hereby or thereby will not, create any Liens on
any assets (including the Assets) of Seller in favor of third parties.

     4.4  Title to Assets.  Seller and Seller's bankruptcy estate own and hold
          ---------------                                                     
of record the entire fight, title and interest in and to all of the Assets, free
and clear of any and all Liens, except the liens held by Buyer and the interests
held by MAC.

     4.5  VDC Shares to Be Issued Pursuant to Plan or Constitute Restricted
          -----------------------------------------------------------------
Securities.  Seller represents and warrants: (I) (a) that it will prepare and
----------                                                                   
file a plan of reorganization and disclosure statement pertaining thereto, as
soon as is practicable and in no event later than the original period fixed by
(S) 1121(b) of the Bankruptcy Code, (b) that this Agreement, the transactions
contemplated hereby and the issuance and distribution of the VDC Shares are and
will be under and in accordance with such plan as contemplated by (S) 1145 of
the Bankruptcy Code, or (II) upon Seller's failure to obtain a declaration from
the Court that the issuance of the VDC Shares is exempt from registration
pursuant to Bankruptcy Code (S) 1145, (a) that it has reviewed the annual and
periodic reports of Buyer, as filed by Buyer with the SEC pursuant to the
Securities Exchange Act of 1934, and that it has such knowledge and experience
in financial and business matters that it is capable of utilizing the
information set forth therein concerning Buyer to evaluate the risks of
investing in the VDC Shares; (b) that it has been advised that the VDC Shares to
be issued by Buyer constitute "restricted securities" as defined in Rule 144
promulgated under the Securities Act, and accordingly, have not been and will
not be registered under the Securities Act except as otherwise set forth in this
Agreement, and, therefore, it may not be able to sell or otherwise dispose of
such VDC Shares except if the VDC Shares are subject to an effective
registration statement filed with the SEC, in compliance with Rule 144 or
otherwise pursuant to an exemption from registration under the Act; (c) that the
VDC Shares so issued are being acquired by them for their own benefit and on
their own behalf for investment purposes and not with a view to, or for sale or
for resale in connection with, a public offering or re-distribution thereof, (d)
that the VDC Shares so issued will not be resold (i) without registration
thereof under the Securities Act (unless an opinion of counsel acceptable to
VDC, or to Buyer, an exemption from such registration is available), (ii) in
violation of any law; and (e) that the certificate or certificates representing
the VDC Shares to be issued will be imprinted with a legend in form and
substance as follows:

          THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
          REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED.  THESE
          SECURITIES MAY NOT BE SOLD, TRANSFERRED OR OTHERWISE DISPOSED OF IN
          THE ABSENCE OF REGISTRATION, OR THE AVAILABILITY OF AN EXEMPTION FROM
          REGISTRATION, UNDER THE SECURITIES ACT OF 1933, AS AMENDED, BASED ON
          AN OPINION LETTER OF COUNSEL FOR THE COMPANY OR A

                                       8
<PAGE>
 
          NO-ACTION LETTER FROM THE SECURITIES AND EXCHANGE COMMISSION.

and Buyer is hereby authorized to notify the transfer agent of the status of the
VDC Shares, and to take such other action including, but not limited to, the
placing of a "stop transfer" order on the books and records of Buyer's transfer
agent to ensure compliance with the foregoing,

     4.6  Brokers' Fees.  No broker, finder or other person or entity acting in
          -------------                                                        
a similar capacity has participated on behalf of Seller in connection with the
transactions contemplated by this Agreement.  Seller has not incurred any
Liability for brokers' fees, finders' fees, agents' commissions or other similar
forms of compensation in connection with this Agreement or the transactions
contemplated hereby.

     4.7  Avoidance.  The transactions contemplated hereby are not subject to
          ---------                                                          
avoidance as fraudulent transfers or fraudulent conveyances under applicable
non-bankruptcy law or the Bankruptcy Code.

     4.8  Fair Value.  Seller acknowledges and agrees that the Purchase Price
          ----------                                                         
constitutes fair, adequate and reasonably equivalent consideration in exchange
for the Assets.

     4.9  Full Disclosure.  No representation or warranty by Seller in this
          ---------------                                                  
Agreement and no statement contained in any Disclosure Schedule to this
Agreement contains any untrue statement of a material fact, or omits to state a
material fact necessary to make the statements contained therein, in light of
the circumstances in which they are made, not misleading.

                                   ARTICLE 5

                    REPRESENTATIONS AND WARRANTIES OF BUYER

     Buyer represents and warrants to Seller as follows:

     5.1  Organization and Standing of Buyer.  Buyer is a corporation duly
          ----------------------------------                              
organized, validly existing and in good standing under the laws of the
Commonwealth of Bermuda.

     5.2  Authorization and Enforceability.  Buyer has all requisite corporate
          --------------------------------                                    
power and authority to enter into this Agreement and the Related Documents to
which it is a party and to carry out the transactions contemplated hereby and
thereby and to perform its obligations hereunder and thereunder.  All necessary
and appropriate action has been taken by Buyer with respect to the execution and
delivery of this Agreement and each of the Related Documents and the performance
of its obligations hereunder and thereunder.  The execution and delivery of this
Agreement and the Related Documents and the consummation of the contemplated
transactions by Buyer will not (a) result in the breach of any of the terms or
conditions of, or constitute a default under, the Certificate of Incorporation
or the By-Laws of Buyer or (b) violate any Law or any order, writ, injunction or

                                       9
<PAGE>
 
decree of any Governmental Authority.  This Agreement and any Related Documents
to which Buyer is a party constitute valid and binding obligations of Buyer
enforceable against Buyer in accordance with their respective terms.

     5.3  VDC Shares.  The VDC Shares delivered by Buyer at Closing will be
          ----------                                                       
validly and legally issued, free and clear of any and all Liens, and will be
fully paid and non-assessable, except that in the event the Court does not
declare that the issuance of the VDC Shares are under a plan in Seller's
bankruptcy case pursuant to Bankruptcy Code (S) 1145, the VDC Shares shall be
"restricted securities" pursuant to Rule 144 promulgated under the Act and
except for the restrictions on resale set forth in Section 7.6 hereof

     5.4  Approval.  The Board of Directors of the Buyer has approved the
          --------                                                       
execution of this Agreement and the transactions contemplated thereby.

     5.5  Brokers' Fees.  Buyer has not incurred any liability for brokers'
          -------------                                                    
fees, finders' fees, agents' commissions or other similar forms of compensation
in connection with this Agreement or the transactions contemplated hereby.

     5.6  Full Disclosure.  No representation or warranty by Buyer in this
          ---------------                                                 
Agreement contains any untrue statement of a material fact or omits to state a
material fact necessary to make the statements contained therein, in light of
the circumstances in which they are made, not misleading.

                                   ARTICLE 6

                                    CLOSING

     6.1  Closing.  Subject to satisfaction or waiver of all conditions
          -------                                                      
precedent set forth in Sections 8 and 9 of this Agreement, the closing of the
transactions contemplated by this Agreement (the "Closing") shall take place at
the offices of Buchanan Ingersoll Professional Corporation, at 10:00 a.m., local
time the day on which the last of the conditions precedent set forth in either
Section 8 or 9 of this Agreement is fulfilled (the "Closing Date") or at such
other time, date and place as the parties may agree, but in no event shall such
date be later than April 30, 1998.

     6.2  Obligations of Seller.  At or prior to the Closing, Seller shall
          ---------------------                                           
deliver to Buyer, in each case, in form and substance satisfactory to Buyer:

          (a) a written release by all of the parties to the Termination
Agreement agreeing to the release of the MAC Common Stock to the Buyer;

          (b) written evidence from MAC confirming that, as of the Closing Date,
no part of the Assets pledged as collateral under the Termination Agreement has
been sold, assigned, transferred or otherwise disposed of or subject to any
action for any of the foregoing (other than the transaction contemplated in this
Agreement), and that, as of the Closing Date, neither MAC nor its

                                       10
<PAGE>
 
parent corporation, Metromedia International Group, Inc., contemplates taking
any of the foregoing actions;

          (c) such other instruments of transfer as shall be necessary or
appropriate to vest in the Buyer good and marketable title to the Assets;

          (d) such other documents as may be described in Article 8 of this
                                                          ---------        
Agreement; and

          (e) a certified copy of the Order approving this Agreement and
authorizing Seller to consummate the transactions contemplated hereby.

     6.3  Obligations of Buyer.  At the Closing, Buyer shall deliver:
          --------------------                                       

          (a) the Purchase Price in accordance with Article 3 of this Agreement;
                                                    ---------                   

          (b) a Deferred Purchase Price Note, in form and substance mutually
satisfactory to the parties hereto;

          (c) evidence of the satisfaction of the Indebtedness; and

          (d) such other documents as may be described in Article 9 of this
                                                          ---------        
Agreement.

     6.4  Further Documents or Necessary Action.  Buyer and Seller each agree to
          -------------------------------------                                 
take all such further actions on or after the Closing Date as may be necessary,
desirable or appropriate in order to confirm or effectuate the transactions
contemplated by this Agreement.

                                   ARTICLE 7

                            COVENANTS AND AGREEMENTS

     Seller covenants to and agrees with Buyer, and Buyer covenants to and
agrees with Seller, as follows:

     7.1  Conduct of Business Pending the Closing.  During the period from the
          ---------------------------------------                             
date of this Agreement to the Closing Date, Seller shall conduct its business
operations in the ordinary and usual course and to maintain its records and
books of account in a manner consistent with prior periods. Seller shall,
without purporting to make any commitment on behalf of Buyer, exercise
reasonable efforts to preserve intact the present business organization and
personnel of Seller and the present goodwill of Seller with persons having
business dealings with them.  Except as otherwise required or contemplated
hereby, Seller further covenants and agrees that, from the date of this
Agreement to the Closing Date, it shall not, without the written consent of
Buyer:

                                       11
<PAGE>
 
          (a) enter into any negotiations, discussions or agreements
contemplating, affecting or respecting the Assets or Seller's ability to
transfer the Assets;

          (b) enter into any negotiations, discussions or agreements
contemplating or respecting the acquisition of Seller or any material asset
thereof (other than in the ordinary course of business), whether through a sale
of stock, a merger or consolidation, the sale of all or substantially all of the
assets of Seller, any type of recapitalization or otherwise, with the exception
of the Seller's interest in and to its Cambodian venture, the disposition of
which has been discussed with the Buyer;

          (c) incur any Liabilities or take any action that would diminish the
value of the Assets;

          (d) take any action which would interfere with or prevent performance
of this Agreement; or

          (e) engage in any activity or enter into any transaction which would
be inconsistent in any respect with any of the representations, warranties or
covenants set forth in this Agreement, as if such representations, warranties
and covenants were made at a time subsequent to such activity or transaction and
all references to the date of this Agreement were deemed to be such later date.

     7.2  Access By Buyer, Confidentiality.  During the period from the date of
          --------------------------------                                     
this Agreement to the Closing Date, Seller shall cause Buyer, its agents and
representatives to be given full access during normal business hours to the
premises, buildings, offices, books, records, assets (including the Assets),
Liabilities, operations, contracts, files, personnel, financial and tax
information and other data and information of Seller, and shall cooperate with
Buyer in conducting its due diligence investigation of Seller; provided that
                                                               --------     
such access shall not unreasonably interfere with the normal operations and
employee relationships of Seller.  All information provided to or teamed by
Buyer as a result of such access or otherwise in connection with the
transactions contemplated by this Agreement shall be held in confidence.

     7.3  Access By Seller, Confidentiality.  During the period from the date of
          ---------------------------------                                     
this Agreement to the Closing Date, Buyer shall cause Seller, its agents and
representatives to be given full access during normal business hours to the
premises, buildings, offices, books, records, assets, liabilities, operations,
contracts, files, personnel, financial and tax information and other data and
information of Buyer, and shall cooperate with Seller in conducting its due
diligence investigation of Buyer; provided that such access shall not
                                  --------                           
unreasonably interfere with the normal operations and employee relationships of
Buyer.  Buyer shall provide Seller with copies of all reports and/or findings
made with the Securities and Exchange Commission from the date hereof through
the Closing.  All information provided to or learned by Seller as a result of
such access or otherwise in connection with the transactions contemplated by
this Agreement shall be held in confidence.

                                       12
<PAGE>
 
     7.4  Notice of Breach or Failure of Condition.  Seller and Buyer agree to
          ----------------------------------------                            
give prompt notice to the others of the occurrence of any event or the failure
of any event to occur that might preclude or interfere with the timely
satisfaction of any condition precedent to the obligations of Seller or Buyer
under this Agreement.

     7.5  Best Efforts.  Seller and Buyer shall use their respective best
          ------------                                                   
efforts to obtain all consents or approvals necessary to bring about the
satisfaction of the conditions required to be performed, fulfilled or complied
with by them pursuant to this Agreement and to take or cause to be taken all
action, and to do or cause to be done all things, necessary, proper or advisable
under applicable Laws to consummate and make effective the transactions
contemplated by this Agreement as expeditiously as practicable.

     7.6  Registration Rights Agreement.
          ----------------------------- 

          (a)  Buyer agrees that, to the extent that the VDC shares may not be
transferred by Seller pursuant to the provisions of Section 1145 of the
Bankruptcy Code, within forty-five (45) days after the Closing Date, it shall,
at its sole expense, use its best efforts to file with the SEC a registration
statement (the "Registration Statement") which shall register (i) the
distribution of the VDC Shares to the stockholders of Seller and (ii) the
distribution of the VDC Shares delivered to third parties by the Seller in
satisfaction of claims against Seller and its bankruptcy estate.  Resale of the
VDC Shares shall be subject to the following limitations

               (i) 25% of the VDC Shares may be sold upon the date of
          declaration of the effectiveness of the Registration Statement;

               (ii) 25% of the VDC Shares may be sold upon the six month
          anniversary of the date of declaration of effectiveness of the
          Registration Statement; and

               (iii) the remaining 50% of the VDC Shares may be sold upon the
          one year anniversary of the date of declaration of effectiveness of
          the Registration Statement.

          (b)  Notwithstanding the rights granted hereunder, Buyer shall have no
obligation whatsoever to:

               (i) assist or cooperate in the offering or disposition of the VDC
          Shares;

               (ii) indemnify or hold harmless the holders of the VDC Shares or
          any underwriter designated by such security holders;

               (iii) obtain a commitment from an underwriter relative to the
          sale of the VDC Shares, or

                                       13
<PAGE>
 
               (iv) include the VDC Shares within an underwritten offering of
          Buyer.

     7.7  Loans.  Buyer agrees to make advances, in its sole discretion, to the
          -----                                                                
Seller under and in accordance Loan, Security and Pledge Agreement, with such
advances being applied against the Purchase Price pursuant to Section 3.4 hereof

     7.8  Exclusive Dealing.  In consideration of Buyer expending considerable
          -----------------                                                   
time and expenses in connection with the transactions contemplated in this
Agreement, including those incurred for due diligence inquiries and legal fees,
Seller hereby covenants and agrees that until the later of (i) sixty (60) days
after the date on which this Agreement automatically expires pursuant to Section
11.5 and (ii) the date on which this Agreement is terminated pursuant to
Sections 11.1, 11.2 or 11.3, Seller will not, directly or indirectly, through
any representative or otherwise, solicit or entertain offers from, negotiate
with or in any manner encourage, discuss, accept or consider any proposal of any
other person relating to the acquisition of the Assets, in whole or in part,
whether directly or indirectly, through purchase, merger, consolidation or
otherwise, except as otherwise may be required by law or order of the Court.

     7.9  Good Faith.  Seller and Buyer have each acted and negotiated this
          ----------                                                       
Agreement in good faith.  This Agreement represents an arms-length agreement
among the parties, absent collusion, coercion or duress.  The Purchase Price to
be paid by the Buyer for the Assets in accordance herewith, represents the fair
and reasonably equivalent value of and for the Assets.  Further, the Order
approving this Agreement shall provide that the reversal or modification or
appeal thereof will not affect the validity of the Closing of the sale of the
Assets to Buyer under and in accordance with such Order by virtue of specific
findings that the Buyer purchased the Assets in good faith, unless such Order is
stayed prior to the Closing.

     7.10  Bidding Procedures.  Seller covenants and agrees that it will seek
           ------------------                                                
expedited consideration by the Court of the approval of this Agreement, together
with approval of bidding procedures acceptable to Buyer and approval of the
Break-Up Fee provided for in Section 11.4 below.  In the event that the Court
makes the sale of the Assets to Buyer subject to the submission of higher and
better offers, the following procedure, among others agreed to by Buyer, will
govern the submission of any Competing Bid as follows:

          (a) The Competing Bid shall provide for consideration that exceeds the
Purchase Price offered by Buyer by at least $1,100,000 (taking into effect that
portion of the Purchase Price resulting from the forgiveness of the
Indebtedness), and if the successful highest bidder is not Buyer, deliver to
Seller at the hearing scheduled for the approval of this Agreement a
nonrefundable deposit payable in cash or by certified or cashier's check in an
amount equal to IO% of successful highest Competing Bid;

          (b) The amount of the Competing Bid for purposes of paragraph (a)
above shall not be on terms which are more burdensome or conditional in any
material respect than the terms hereof;

                                       14
<PAGE>
 
          (c) The form of the Competing Bid must be in the form of a final
written contract signed by the competing bidder which, when and if approved by
the Court, can be immediately countersigned by the Seller and shall form a
binding agreement between the parties thereto;

          (d) The Competing Bid shall not be contingent upon receipt of
financing necessary to its consummation; and

          (e) The Competing Bid shall not be conditioned on the outcome of
unperformed due diligence by the competing bidder with respect to the business
or the Seller's Assets; and the competing bidder shall be obligated to close
prior to July 1, 1998.

          (f) If any Competing Bid does not conform to paragraphs (a) through
(e) above, such bid will not be considered by the Court or be admissible at such
hearing.

     7.11  Cooperation.  Seller and Buyer agree that they will cooperate in good
           -----------                                                          
faith with respect to all proceedings before the Court in the case in connection
with the approval and consummation of this Agreement and the transactions
contemplated hereby.

                                   ARTICLE 8

                  CONDITIONS PRECEDENT TO OBLIGATIONS OF BUYER

     All obligations of Buyer under this Agreement are subject to the
satisfaction by Seller at or before the Closing of all of the following
conditions, except to the extent expressly waived in writing by Buyer:

     8.1  Representations and Warranties True at Closing.  The representations
          ----------------------------------------------                      
and warranties of Seller contained in this Agreement shall have been true and
correct in all material respects when made and shall be true and correct in all
material respects on the Closing Date as though such representations and
warranties were made again on the Closing Date.

     8.2  Performance.  Seller shall have performed and complied in all material
          -----------                                                           
respects with all agreements and conditions required by this Agreement to be
performed or complied with by Seller prior to or at the Closing, including,
without limitation, the delivery to Buyer of the documents listed in Section
6.2.

     8.3  No Adverse Changes.  Except as contemplated by this Agreement, there
          ------------------                                                  
shall have been no material adverse change in the condition, prospects, business
or operations, financial or otherwise, of Seller from the date of this Agreement
to the Closing Date.

     8.4  Litigation.  On the Closing Date, there shall not be any pending or
          ----------                                                         
threatened litigation in any court or any proceedings by or before any
Governmental Authority with a view to seek, or in which it is sought, to
restrain or prohibit the consummation of the transactions 

                                       15
<PAGE>
 
contemplated by this Agreement or in which it is sought to obtain divestiture,
rescission or damages in connection with the transactions contemplated by this
Agreement and no investigation by any Governmental Authority shall be pending
which might result in any such litigation or other proceeding.

     8.5  Necessary Consents.  All statutory requirements for the valid
          ------------------                                           
consummation by Buyer of the transactions contemplated by this Agreement shall
have been fulfilled and all authorizations, consents, waivers, approvals or
other actions by any Governmental Authority or third party which are required
for the consummation of the transactions contemplated by this Agreement shall
have been received and shall be in full force and effect.

     8.6  Stockholder Approval.  To the extent required by the laws of Bermuda,
          --------------------                                                 
the stockholders of Buyer shall have approved the transactions contemplated by
this Agreement.

     8.7  Certificate.  Seller shall have delivered to Buyer a certificate,
          -----------                                                      
dated as of the Closing Date, of the Seller to the effect that the conditions
set forth in Sections 8.1, 8.2, 8.3, 8.4 and 8.8 have been satisfied.
             ---------------------------     ---                     

     8.8  Consents.  Seller shall have provided written consents to the
          --------                                                     
acquisition of the Assets by Buyer from all appropriate Governmental Authorities
(to the extent so required by law) in form and substance reasonably acceptable
to Buyer.

     8.9  Due Diligence.  Buyer shall have completed, to its satisfaction, a due
          -------------                                                         
diligence review of the financial condition, results of operations, properties,
assets, liabilities, business and prospects of Seller.

     8.10  Evidence of Satisfaction of Indebtedness.  Seller shall have provided
           ----------------------------------------                             
validly executed releases, waivers and/or settlement agreements, satisfactory in
form and substance to Buyer, evidencing agreements for the satisfaction of
substantially all indebtedness of, and claims against, Seller.

     8.11  Court Approval.  The Court shall have entered an Order in form and
           --------------                                                    
substance satisfactory to Buyer, approving this Agreement, authorizing the
transactions contemplated hereby, replacing the Liens on the Assets by granting
to the holders thereof Liens in and on the Purchase Price and authorizing the
sale of the Assets free and clear of all Liens, which Order shall not be subject
to a pending appeal, or motion for reconsideration, modification, vacation or
stay, and as to which the time to file such appeal or motion has expired, or any
such appeal or motion that may have been filed has been dismissed with prejudice
or otherwise disposed of without impacting negatively the Order contemplated
hereby.  Further, such Order shall recognize Buyer's rights with respect to the
Indebtedness under Bankruptcy Code (S) 363(k), shall declare the parties' good
faith in all respects under and in accordance with Bankruptcy Code (S) 363(m),
and shall give full effect to the Break-Up Fee, bidding and exclusive dealing
provisions hereof

                                       16
<PAGE>
 
                                   ARTICLE 9

                 CONDITIONS PRECEDENT TO OBLIGATIONS OF SELLER

     All obligations of Seller under this Agreement are subject to the
satisfaction by Buyer at or before the Closing of all of the following
conditions, except to the extent expressly waived in writing by Seller:

     9.1  Representations and Warranties True at Closing.  The representations
          ----------------------------------------------                      
and warranties of Buyer contained in this Agreement shall have been true and
correct in all material respects when made and shall be true and correct in all
material respects on the Closing Date as though such representations and
warranties were made again on the Closing Date; provided, however, that if Buyer
changes its jurisdiction of incorporation from the Commonwealth of Bermuda to
the State of Delaware on or before the Closing Date, Buyer shall be deemed to
represent in Section 5.1 that it is a corporation duly organized, validly
existing and in good standing under the laws of the State of Delaware.

     9.2  Performance.  Buyer shall have performed and complied, in all material
          -----------                                                           
respects, with all agreements and conditions required by this Agreement to be
performed or complied with by Buyer prior to or at the Closing.

     9.3  No Adverse Changes.  Except as contemplated by this Agreement, there
          ------------------                                                  
shall have been no material adverse change in the condition, business or
operations, financial or otherwise, of Buyer from the date of this Agreement to
the Closing Date.

     9.4  Necessary Consents.  All statutory requirements for the valid
          ------------------                                           
consummation by Seller of the transactions contemplated by this Agreement shall
have been fulfilled and all authorizations, consents, waivers, approvals or
other actions by any Governmental Authority or third party which are required
for the consummation of the transactions contemplated by this Agreement shall
have been received and shall be in full force and effect.

     9.5  Certificate.  Buyer shall have delivered to Seller a certificate,
          -----------                                                      
dated as of the Closing Date, to the effect that the conditions set forth in
Sections 9.1, 9.2 and 9.3 have been satisfied.

     9.6  Court Approval.  The Court shall have entered an Order in form and
          --------------                                                    
substance satisfactory to Seller, approving this Agreement, authorizing the
transactions contemplated hereby, replacing the Liens on the Assets by granting
to the holders thereof Liens in and on the Purchase Price and authorizing the
sale of the Assets free and clear of all Liens.

     9.7  Indebtedness.  Seller shall be obligated to perform hereunder and
          ------------                                                     
Close the transactions contemplated hereby notwithstanding the occurrence of an
Event of Default under the documents evidencing the Indebtedness or Buyer's
exercise of any rights or remedies thereunder, including, without limitation,
Seller shall continue to seek approval of this Agreement with respect 

                                       17
<PAGE>
 
to the MAC Shares following Buyer's exercise of its right to retain possession
of the MAC Warrants in satisfaction of the Indebtedness and the Purchase Price
shall be adjusted by reducing the Purchase Price by the Indebtedness and Cash
Funds, resulting in the VDC Shares and Deferred Purchase Price being exchanged
for the Assets.

                                   ARTICLE 10

                      INDEMNIFICATION AND RELATED MATTERS

     10.1  Survival of Representations and Warranties.  The representations and
           ------------------------------------------                          
warranties contained in this Agreement, the schedules and exhibits hereto, and
any agreement, document, instrument or certificate delivered hereunder,
including the Related Documents, shall survive the Closing Date.  This Article
                                                                       -------
10 constitutes the sole and exclusive remedy of Buyer and Seller with respect to
--                                                                              
any subject matter addressed herein, and Buyer and Seller hereby waive and
release the other from any and all claims and other causes of action, including
without limitation claims for contribution, relating to any such subject matter.

     10.2  Indemnification by Seller.
           ------------------------- 

          (a) Seller agrees to indemnify Buyer against and hold it harmless
from:

               (i) all liability, loss, damage or deficiency resulting from or
          arising out of any inaccuracy in or breach of any representation or
          warranty by Seller in this Agreement, in any Related Document to which
          Seller was a signatory or in any other agreement or document delivered
          by or on behalf of Seller in connection with the transactions
          contemplated by this Agreement;

               (ii) all liability of Seller not expressly assumed by Buyer;

               (iii) all liability, loss, damage or deficiency resulting from or
          arising out of any breach or nonperformance of any covenant or
          obligation made or incurred by Seller in this Agreement, in any
          Related Document to which Seller was a signatory or in any other
          agreement or document delivered by or on behalf of Seller in
          connection with the transactions contemplated by this Agreement; and

               (iv) any and all reasonable costs and expenses (including
          reasonable legal and accounting fees) related to any of the foregoing.
          In the event that Buyer makes a Claim which is determined by a court
          of competent jurisdiction to be without reasonable basis in law or
          fact, Buyer shall bear all reasonable costs and expenses (including
          court costs and reasonable legal and accounting fees), incurred by
          Seller in investigating and defending against such Claim,

                                       18
<PAGE>
 
which indemnification obligation of Seller shall be secured by the Deferred
Purchase Price and the VDC Shares that remain unissued and Buyer shall have the
fight of offset with respect thereto.

     10.3  Indemnification by Buyer.  Buyer shall indemnify Seller against and
           ------------------------                                           
hold it harmless from:

          (a) all liability, loss, damage or deficiency resulting from or
arising out of any inaccuracy in or breach of any representation or warranty by
Buyer in this Agreement in any Related Document or in any other agreement or
document delivered by or on behalf of Buyer in connection with the transactions
contemplated by this Agreement;

          (b) all liability, loss, damage or deficiency resulting from or
arising out of any breach or nonperformance of any covenant or obligation made
or incurred by Buyer in this Agreement, in any Related Document, or in any other
agreement or document delivered by or on behalf of Buyer in connection with the
transactions contemplated by this Agreement, and

          (c) any and all reasonable costs and expenses (including reasonable
legal and accounting fees) related to any of the foregoing.  In the event that
Seller makes a Claim which is determined by a court of competent jurisdiction to
be without reasonable basis in law or fact, Seller shall bear all reasonable
costs and expenses (including court costs and reasonable legal and accounting
fees), incurred by Buyer in investigating and defending against such Claim.

     10.4  Third Party Claims.  If any action, suit, investigation or proceeding
           ------------------                                                   
(including without limitation negotiations with federal, state, local or foreign
tax authorities) shall be threatened or commenced by a third party in respect of
which a party (an "Indemnified Party") may make a Claim hereunder, the
Indemnified Party shall notify the party obligated to indemnify such party
hereunder (the "Indemnifying Party") to that effect with reasonable promptness
(so as to not prejudice such party's rights) after the commencement or
threatened commencement of such action, suit, investigation or proceeding, and
the Indemnifying Party shall have the opportunity to defend against such action,
suit, investigation or proceeding (or, if the action, suit, investigation or
proceeding involves to a significant extent matters beyond the scope of the
indemnity agreement contained herein, those claims that are covered hereby)
subject to the limitations set forth below. If the Indemnifying Party elects to
defend against any action, suit, investigation or proceeding (or, as described
in the preceding parenthetical, one or more claims relating thereto), the
Indemnifying Party shall notify the Indemnified Party to that effect with
reasonable promptness.  In such case, the Indemnified Party shall have the fight
to employ its own counsel and participate in the defense of such matter, but the
fees and expenses of counsel shall be at the expense of the Indemnified Party
unless the employment of such counsel at the expense of the Indemnifying Party
shall have been authorized in writing by the Indemnifying Party.  Any party
granted the right to direct the defense of a threatened or actual suit,
investigation or proceeding hereunder shall: (i) keep the other fully informed
of material developments in the action, suit, investigation or proceeding at all
stages thereof, (ii) promptly submit to the other copies of all pleadings,
responsive pleadings, motions and other similar legal documents and papers
received in connection with the action, suit, investigation 

                                       19
<PAGE>
 
or proceeding; (iii) permit the other and its counsel, to the extent
practicable, to confer on the conduct of the defense of the action, suit,
investigation or proceeding; and (iv) to the extent practicable, permit the
other and its counsel an opportunity to review all legal papers to be submitted
prior to their submission. The parties shall make available to each other and
each other's counsel and accountants all of its or their books and records
relating to the action, suit, investigation or proceeding, and each party shall
render to the other such assistance as may be reasonably required in order to
insure the proper and adequate defense of the action, suit, investigation or
proceeding. The parties shall use their respective good faith efforts to avoid
the waiver of any privilege of either party. The assumption of the defense of
any matter by an Indemnifying Party shall not constitute an admission of
responsibility to indemnify or in any manner impair or restrict such party's
fights to later seek to be reimbursed its costs and expenses if indemnification
under this Agreement with respect to such matter was not required. An
Indemnifying Party may elect to assume the defense of a matter at any time
during the pendency of such matter, even if initially such party did not elect
to assume such defense, so long as such assumption at such later time would not
prejudice the fights of the Indemnified Party. No settlement of a matter by the
Indemnified Party shall be binding on an Indemnifying Party for purposes of such
party's indemnification obligations hereunder.

                                   ARTICLE 11

                                  TERMINATION

     11.1  Termination by Mutual Consent.  At any time on or prior to the 
           -----------------------------   
Closing Date, this Agreement may be terminated by the mutual written consent of
Seller and Buyer without liability on the part of Seller or Buyer.

     11.2  Termination Upon Breach or Default.  If Seller or Buyer shall
           ----------------------------------                           
materially default in the observance or in the due and timely performance of any
of the covenants contained in this Agreement, or if there shall have been a
material breach by either of the parties of any of the representations or
warranties set forth in this Agreement, the other party may, upon written notice
and a reasonably opportunity to cure, terminate this Agreement, without
prejudice to its rights and remedies available at law, including the fight to
recover expenses, costs and other damages.

     11.3  Termination Based Upon Failure of Conditions.  If any of the
           --------------------------------------------                
conditions of this Agreement to be complied with or performed by a party on or
before the Closing Date, shall not have been complied with or performed in all
material respects by such date and such noncompliance or nonperformance shall
not have been waived in writing by the other party, the party to whom the
benefit of such condition runs may, upon written notice, terminate this
Agreement, without prejudice to its or their rights and remedies available under
law, including the right to recover expenses, costs and other damages.

     11.4  Break-Up Fees.  Notwithstanding anything to the contrary contained
           -------------                                                     
within this Agreement, in the event Seller is unable to, or elects not to
complete the transactions contemplated by this Agreement for any reason, except:
(i) a breach by Buyer of any of its representations, 

                                       20
<PAGE>
 
warranties and covenants contained herein or (ii) a material adverse development
in the business or operations of Buyer between the date of this Agreement and
the Closing Date, then; and in that event, Seller shall pay Buyer a break-up fee
equal to One Million Dollars ($1,000,000) ("Break-Up Fee") in order to reimburse
Buyer for its time and expenses incurred in connection with the transactions
contemplated in this Agreement, as well as for any lost opportunity costs and
direct and indirect consequential damages. Payment of the Break-Up Fee shall be
made by wire transfer of immediately available funds to an account designated by
Buyer not later than five (5) days after receipt by Seller of a written demand
for the Break-Up Fee by Buyer, but in no case later than Seller's receipt of
proceeds from the sale or other disposition of the Assets, directly or
indirectly. Seller acknowledges that any payment of the Break-Up Fee will be
treated as one for liquidated damages and not a penalty, such being agreed
between Buyer and Seller to be a necessary condition to this Agreement to
compensate Buyer for expenses and expenditures incurred and made in connection
herewith and otherwise for Seller's non-compliance with this Agreement.

     11.5  Final Expiration.  This Agreement shall automatically expire if the
           ----------------                                                   
Closing does not occur on or before April 30, 1998, or, upon such later date as
VDC in its sole discretion may determine; provided, however, that such later
date shall not be later than July 1, 1998.

                                   ARTICLE 12

                                    GENERAL

     12.1  Entire Agreement.  This Agreement, and the exhibits and schedules
           ----------------                                                 
hereto (including the Disclosure Schedule), and the agreements specifically
referred to herein, including the documents evidencing the Indebtedness, set
forth the entire agreement and understanding of Seller and Buyer in respect of
the transactions contemplated hereby and, except with respect to the provisions
of Section 13 of the Letter of Intent and the no shop provisions set forth in
Section 8 of the Letter of Intent, supersede all prior agreements, arrangements
and understandings relating to the subject matter hereof No representation,
promise, inducement or statement of intention has been made by Seller or Buyer
that is not embodied in this Agreement or in the documents specifically referred
to herein and neither Seller nor Buyer shall not be bound by or liable for any
alleged representation, promise, inducement or statement of intention not so set
forth.

     12.2  Binding Effect, Benefits, Assignment.  Upon the entry of an Order by
           ------------------------------------                                
the Court approving this Agreement, all of the terms of this Agreement shall be
binding upon, inure to the benefit of and be enforceable by and against Seller
and its successors and authorized assigns, and Buyer and its successors and
authorized assigns.  Nothing in this Agreement, express or implied, is intended
to confer upon any other person any rights or remedies under or by reason of
this Agreement except as expressly indicated herein.  Neither Seller nor Buyer
shall assign any of their respective rights or obligations under this Agreement
to any other person, firm or corporation without the prior written consent of
the other party, except that Buyer may assign its rights and obligations under
this Agreement to a direct or indirect wholly-owned subsidiary of Buyer,
although Buyer shall remain fully responsible for all of its obligations under
this Agreement.

                                       21
<PAGE>
 
     12.3  Construction.  The headings of the sections and paragraphs of this
           ------------                                                      
Agreement have been inserted for convenience of reference only and shall in no
way restrict or otherwise modify any of the terms or provisions hereof The
language used in this Agreement shall be deemed to be the language chosen by the
parties to this Agreement to express their mutual intent, and no rule of strict
construction shall be applied against any party.

     12.4  Amendment and Waiver.  This Agreement may be amended, modified,
           --------------------                                           
superseded or canceled and any of the terms, covenants, representations,
warranties or conditions hereof may be waived only by a written instrument
executed by Seller and Buyer or, in the case of a waiver, by or on behalf of the
party waiving compliance.

     12.5  Governing Law.  This Agreement shall be governed by and construed in
           -------------                                                       
accordance with the laws of the State of Delaware as applicable to contracts
made and to be performed in Delaware, without regard to conflict of laws
principles.

     12.6  Public Disclosure.  Except as required by Law, or in connection with
           -----------------                                                   
the solicitation of new investment advisory agreements with Seller's clients,
neither Buyer nor Seller shall make any public disclosure of the existence or
terms of this Agreement or the transactions contemplated hereby without the
prior written consent of the other party, which consent shall not be
unreasonably withheld.  In the event that Seller or Buyer determines that the
disclosure of the existence or terms of this Agreement is required by Law, such
party shall so notify the other parties and shall provide to the other party a
copy of any such public disclosure prior to releasing the same.

     12.7  Notices.  All notices, requests, demands and other communications to
           -------                                                             
be given pursuant to the terms of this Agreement shall be in writing and shall
be deemed to have been duly given if hand delivered, sent by overnight mail by a
nationally recognized overnight delivery service or mailed first class, postage
prepaid:

          (a)  If to Seller:

               Michael Richard, President
               PortaCom Wireless, Inc.
               10061 Talbert Avenue, Suite 200
               Fountain Valley, CA  92708
               Telephone:  (714) 593-3234
               Telecopier:  (714) 593-3264

                                       22
<PAGE>
 
               with a copy to:

               Francis A. Monaco, Jr., Esquire
               Walsh and Monzack, P.A.
               1201 Orange Street, Suite 400
               Wilmington, DE  19899
               Telephone:  (302) 656-8162
               Telecopier:  (302) 656-2769

               and

               Jeffrey Kurtzman, Esquire
               Klehr, Harrison, Harvey, Branzburg & Ellers
               1401 Walnut Street
               Philadelphia, PA  19102
               Telephone:  (215) 568-4493
               Telecopier:  (215) 568-6603

          (b)  If to Buyer:

               Frederick A. Moran, Chief Executive Officer
               VDC Corporation Ltd.
               27 Doubling Road
               Greenwich, CT  06830
               Telephone:  (203) 661-9600
               Telecopier:  (203) 869-1430

               with a copy to:

               Stephen M. Cohen, Esq.
               Stuart M. Brown, Esq.
               Buchanan Ingersoll Professional Corporation
               Eleven Penn Center, 14th Floor
               1835 Market Street
               Philadelphia, Pennsylvania  19103
               Telephone:  (215) 665-3873
               Telecopier:  (215) 665-8760

Either party may change its address by prior written notice to the other party.

     12.8  Counterparts.  This Agreement may be executed in counterparts, each
           ------------   
of which when so executed shall be deemed to be an original and such
counterparts shall together constitute one and the same instrument.

                                       23
<PAGE>
 
     12.9  Expenses.  Each party shall pay their own respective expenses, costs
           --------                                                            
and fees incurred in connection with the negotiation, preparation, execution and
delivery of this Agreement and each of the Related Documents and the
consummation of the transactions contemplated hereby, including, without
limitation, the fees and expenses of their respective legal counsel, accountants
and financial advisors.

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed as of the day and year first above written.

                                  VDC CORPORATION LTD.


                                  By:_______________________________________
                                     Frederick A. Moran, Chief Executive Officer


                                  PORTACOM WIRELESS, INC.


                                  By:_______________________________________
                                     Michael Richard, President

                                       24
<PAGE>
 
                                   EXHIBIT A

   Indebtedness of Seller to be satisfied from proceeds of the Purchase Price


<TABLE>
<CAPTION>
------------------------------------------------------------------------------
                                                 Source of Proceeds
------------------------------------------------------------------------------
<S>                        <C>              <C>               <C>
Creditor/Claimant          Amount           Cash Funds        VDS Shares
                                             (amount)          (Number)
------------------------------------------------------------------------------

------------------------------------------------------------------------------
                                                                  
------------------------------------------------------------------------------
                                                                  
------------------------------------------------------------------------------
                                                                  
------------------------------------------------------------------------------
                                                                  
------------------------------------------------------------------------------
                                                                  
------------------------------------------------------------------------------
                                                                  
------------------------------------------------------------------------------
                                                                  
------------------------------------------------------------------------------
                                                                  
------------------------------------------------------------------------------
</TABLE>

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