EXHIBIT 10.18

                                                                  EXECUTION COPY

                             OPTIMAL ROBOTICS CORP.

                                   ("Optimal")

                                       and

                               TERRA PAYMENTS INC.

                                    ("Terra")

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                              COMBINATION AGREEMENT

                                      DATED

                                January 20, 2004

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                                TABLE OF CONTENTS

                                                                            Page

ARTICLE 1 DEFINITIONS AND PRINCIPLES OF INTERPRETATION.........................3
   1.1   Definitions...........................................................3
   1.2   Certain Rules of Interpretation......................................11
   1.3   Entire Agreement.....................................................13
   1.4   Schedule.............................................................13
   1.5   Accounting Matters...................................................13
   1.6   Knowledge............................................................14

ARTICLE 2 THE TRANSACTION.....................................................14
   2.1   The Amalgamation.....................................................14
   2.2   Implementation Steps by Terra........................................14
   2.3   Implementation Steps by Optimal......................................15
   2.4   Joint Proxy Circular.................................................15
   2.5   Closing Matters......................................................16
   2.6   Securities Compliance................................................16
   2.7   Preparation of Filings, etc..........................................16
   2.8   Treatment of Stock Option Plans and Warrants.........................17

ARTICLE 3 REPRESENTATIONS AND WARRANTIES......................................18
   3.1   Representations and Warranties of Terra..............................18
   3.2   Representations and Warranties of Optimal............................33
   3.3   Survival.............................................................45

ARTICLE 4 COVENANTS...........................................................45
   4.1   Retention of Goodwill................................................45
   4.2   Covenants of Terra...................................................45
   4.3   Covenants of Optimal.................................................51
   4.4   Terra Covenants Regarding Non-Solicitation...........................53
   4.5   Matching Rights......................................................55
   4.6   Access to Information................................................56
   4.7   Optimal Board Designees..............................................57
   4.8   Optimal Covenant Regarding Non-Solicitation..........................57
   4.9   Indemnification......................................................57

ARTICLE 5 CONDITIONS..........................................................58
   5.1   Mutual Conditions Precedent..........................................58
   5.2   Additional Conditions Precedent to the Obligations of Optimal........59
   5.3   Additional Conditions Precedent to the Obligations of Terra..........60
   5.4   Notice and Cure Provisions...........................................62
   5.5   Satisfaction of Conditions...........................................63

ARTICLE 6 AMENDMENT AND TERMINATION...........................................63
   6.1   Amendment............................................................63
   6.2   Termination..........................................................64
   6.3   Break and Other Fees.................................................66
   6.4   Remedies.............................................................67


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                                TABLE OF CONTENTS
                                   (continued)

                                                                            Page

ARTICLE 7 GENERAL.............................................................67
   7.1   Notices..............................................................67
   7.2   Assignment...........................................................69
   7.3   Further Assurances...................................................69
   7.4   Expenses.............................................................69
   7.5   Public Notices.......................................................69
   7.6   Execution and Delivery...............................................70


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                              COMBINATION AGREEMENT

THIS AGREEMENT is made the 20th day of January, 2004

B E T W E E N :

                     OPTIMAL ROBOTICS CORP.

                     a corporation governed by the laws of Canada
                     ("Optimal")

                                     - and -

                     TERRA PAYMENTS INC.

                     a corporation governed by the laws of Canada
                     ("Terra")

RECITALS:

A.    Upon the terms and subject to the conditions of this Agreement (as defined
      in Section 1.1) and in accordance with the Canada Business Corporations
      Act, as now in effect and as it may be amended from time to time prior to
      the Effective Time (as defined in Section 1.1) (the "Act") Optimal and
      Terra intend to enter into a business combination transaction.

B.    The Board of Directors of Terra (i) has determined that the Amalgamation
      (as defined in Section 1.1) and the other transactions contemplated herein
      (collectively, the "Transaction") are fair to, and in the best interests
      of, Terra and its shareholders, (ii) has approved this Agreement, the
      Amalgamation and the other transactions contemplated by this Agreement and
      (iii) has determined to recommend that the shareholders of Terra approve
      the Terra Resolution.

THEREFORE, the parties agree as follows:

                                    ARTICLE 1
                          DEFINITIONS AND PRINCIPLES OF
                                 INTERPRETATION

1.1   Definitions

      In this Agreement, unless there is something in the subject matter or
context inconsistent therewith, the following terms shall have the following
meanings respectively:

      "1933 Act" means the United States Securities Act of 1933;


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      "Acquisition Proposal" means any proposal or offer with respect to any
      merger, amalgamation, arrangement, business combination, liquidation,
      dissolution, recapitalization, take-over bid, tender offer, purchase of
      any assets representing greater than 25% of the fair market value of the
      Transaction, or purchase of more than 20% of the equity (or rights
      thereto) of Terra or a Subsidiary of Terra, or similar transactions or
      series of transactions involving Terra or any of its Subsidiaries,
      excluding the Transaction;

      "Act" has the meaning ascribed to it in the Recitals to this Agreement;

      "Affiliate" has the meaning ascribed to it under the Act;

      "Agreement" means this agreement, including all schedules, and all
      amendments or restatements as permitted, and references to "Article" or
      "Section" mean the specified Article or Section of this agreement;

      "Amalco" means the corporation continuing as a result of the Amalgamation;

      "Amalco Common Shares" means the common shares in the capital of Amalco;

      "Amalgamation" means the amalgamation of Optimal Subco and Terra pursuant
      to the provisions of the Act on the terms and subject to the conditions
      set out in the Amalgamation Agreement, subject to any amendments or
      variations thereto made in accordance with this Agreement;

      "Amalgamation Agreement" means an amalgamation agreement providing for the
      Amalgamation in form and content satisfactory to the Parties, acting
      reasonably;

      "Ancillary Documents" means the Schedules to this Agreement and any
      disclosure letters between the Parties as contemplated in this Agreement;

      "AOL Warrant" means a share purchase warrant issued by Terra to AOL Canada
      Inc. entitling the holder thereof to purchase up to 50,000 Terra Shares at
      an exercise price of $61.50 per share from the vesting date of such
      warrant until October 13, 2005;

      "Arm's Length" has the meaning that it has for purposes of the Income Tax
      Act (Canada);

      "Articles of Amalgamation" means the articles of amalgamation of Terra and
      Optimal Subco in respect of the Amalgamation that are required under the
      Act to be filed with the Director";

      "Balance Sheet" means the consolidated balance sheet of Terra as at March
      31, 2003, forming part of the Financial Statements;

      "Break Fee" means $2,000,000;


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      "Business Day" means any day on which commercial deposit taking banks are
      generally open for business in Montreal, Quebec and New York, New York
      other than a Saturday, a Sunday or a day observed as a holiday in such
      locations under applicable Laws;

      "Change of Control" means any proposal or offer with respect to any
      transaction which would result in any Person or group acquiring ownership,
      directly or indirectly, beneficially or of record, of voting stock of
      Optimal representing more than 50% of the then outstanding stock of
      Optimal entitled to vote for members of the Optimal Board.

      "Confidentiality Agreement" means the confidentiality agreement dated
      January 8, 2004 between Terra and Optimal;

      "Contracts" means a contract, lease, instrument, note, bond, debenture,
      mortgage, agreement, arrangement or understanding to which a Party, or any
      of its subsidiaries, is a party or under which a Party or any of its
      subsidiaries is bound, has unfulfilled obligations or contingent
      liabilities or is owed unfulfilled obligations, whether known or unknown,
      whether asserted or not;

      "CVMQ" means the Commission des valeurs mobilieres du Quebec;

      "Director" means the Director appointed pursuant to the Act;

      "Disclosure Letter" means the disclosure letter provided by Terra to
      Optimal concurrently with the execution of the Agreement, in a form and
      with contents that is accepted by Optimal;

      "Dissent Rights" means the rights of dissent in respect of the
      Amalgamation under Section 190 of the Act;

      "EBS Warrant" means the warrant agreement dated April 1, 2003 between
      Terra and EBS Holding AG pursuant to which EBS Holding AG has the
      non-transferable option to receive 0.21 of a Terra Share for each Terra
      Share issued by Terra pursuant to the exercise of Terra Options granted
      prior to April 1, 2003, at an exercise price of $0.01 per 0.21 of a Terra
      Share so issued.

      "Effective Date" means the date shown on the certificate of Amalgamation
      to be issued under the Act giving effect to the Amalgamation;

      "Effective Time" has the meaning ascribed to it in Section 2.5;

      "End User Laws" means Laws or portions of Laws dealing with or pertaining
      to privacy, personal information, data protection, gaming, lotteries,
      gambling, contests, consumer protection, unfair business practices,
      adhesion contracts, unfair business practices, language, import and export
      restrictions, labeling, packaging and any other related Laws, including
      the Consumer Protection Act, S.Q., c. P-40.1 (Quebec), the Charter of
      French Language, S.Q., c. C-11


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      (Quebec), the Act Respecting the Protection of Personal Information in the
      Private Sector, S.Q., c. P-39.1 (Quebec), the Act Respecting a Legal
      Framework for Information Technology, S.Q., c. C-1.1 (Quebec), the Act
      Respecting Lotteries, Publicity Contests and Amusement Machines, S.Q., c.
      L-6 (Quebec) and the Information Protection and Electronic Documents Act
      (Canada);

      "Environmental Laws" means all applicable Laws relating to the environment
      and employee and public health and safety, including any such
      environmental Laws relating to a discharge, spill, emission or other
      release, whether actual or potential of any contaminant and any other
      applicable Laws;

      "Exchange Act" means the United States Securities Exchange Act of 1934;

      "Exchange Ratio" means 0.4532, being 0.4532 Optimal Shares for each Terra
      Share;

      "Financial Statements" means the audited consolidated financial statements
      of Terra for the fiscal year ended March 31, 2003, including the Balance
      Sheet and the notes to such statements and the unaudited consolidated
      financial statements of Terra for the six months ended September 30, 2003;

      "Governmental Authority" means any (a) multinational, federal, provincial,
      state, regional, municipal, local or other government, governmental or
      public department, central bank, court, tribunal, arbitral body,
      commission, board, bureau or agency, domestic or foreign, (b)
      self-regulatory organization or stock exchange, including NASDAQ and TSX,
      (c) any subdivision, agent, commission, board, or authority of any of the
      foregoing, or (d) any quasi-governmental or private body exercising any
      regulatory, expropriation or taxing authority under or for the account of
      any of the foregoing;

      "Holders" means, when used with reference to the Terra Shares, the holders
      thereof shown from time to time in the register maintained by or on behalf
      of Terra in respect of such securities;

      "Intellectual Property" shall mean any or all of the following and all
      common law and statutory rights in, arising out of, or associated
      therewith: (i) patents and applications therefor and all reissues,
      divisions, renewals, extensions, provisionals, re-extensions,
      continuations and continuations-in-part thereof; (ii) inventions (whether
      patentable or not), invention disclosures, improvements, trade secrets,
      proprietary information, know how, technology, processes, procedures,
      technical data, manuals, records and customer lists, and all documentation
      relating to any of the foregoing; (iii) copyrights, copyright
      registrations and applications therefor, and all other rights
      corresponding thereto; (iv) domain names, uniform resource locators and
      other names and locators associated with the Internet, together with the
      goodwill associated therewith; (v) industrial designs or similar rights
      and any registrations and applications therefor; (vi) trade names, logos,
      common law trademarks and service marks, trademark and service mark


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      registrations and applications therefor, together with the goodwill
      associated therewith; (vii) all databases and data collections and all
      rights therein; (viii) all moral and economic rights of authors and
      inventors, however denominated, and (ix) any similar or equivalent rights
      to any of the foregoing (as applicable);

      "Joint Circular" has the meaning ascribed thereto in Section 2.4;

      "Laws" means all applicable laws (including common law), statutes,
      regulations, statutory rules, orders, ordinances, policies and notices
      having the force of law, and the terms and conditions of any approvals,
      licences or judgments of any applicable published notes and policies of
      any Governmental Authority having the force of law, and the term
      "applicable", with respect to such Laws and in the context that refers to
      one or more Persons, means such Laws that apply to such Person or Persons
      or its or their business, undertaking, property or securities and that
      emanate from a Governmental Authority having jurisdiction over the Person
      or Persons or its or their business, undertaking, property or securities;

      "Material Adverse Change" means, with respect to any Party, any change,
      effect, event or occurrence with respect to the condition (financial or
      otherwise), properties, assets, liabilities, obligations (whether
      absolute, accrued, conditional or otherwise), businesses, operations or
      results of operations or prospects of such Party or those of its
      subsidiaries that is, or could reasonably be expected to be, material and
      adverse to such Party and its subsidiaries on a consolidated basis;
      provided, however, that changes in the trading price for such Party's
      shares shall not constitute, or be considered in determining the existence
      of, a Material Adverse Change;

      "Material Adverse Effect" when used in connection with a Party, means any
      effect of a Material Adverse Change relating to such Party;

      "material fact" has the meaning ascribed to it under the Securities Act
      (Ontario);

      "Meetings" means the Optimal Meeting and the Terra Meeting;

      "NASDAQ" means The NASDAQ Stock Market;

      "New Terra Option" has the meaning ascribed thereto in Section 2.8;

      "Optimal Balance Sheet" means the consolidated balance sheet of Optimal as
      at December 31, 2002, forming part of the Optimal Financial Statements;

      "Optimal Benefit Plans" means all plans, arrangements, agreements,
      programs, policies, practices or undertakings, whether oral or written,
      formal or informal, funded or unfunded, registered or unregistered to
      which Optimal or its Subsidiaries is a party or bound by or under which
      Optimal or its Subsidiaries has, or will have, any liability or contingent
      liability, relating to: pension plans, insurance plans (whether insured or
      self-insured) or compensation plans with respect to any of its employees
      or former employees (or any spouses, dependants,


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      survivors or beneficiaries of any such employees or former employees),
      directors or officers, individuals working on contract with Optimal or its
      Subsidiaries or other individuals providing services to it of a kind
      normally provided by employees or eligible dependants of such person;

      "Optimal Board" has the meaning ascribed to it in Section 4.7;

      "Optimal Disclosure Letter" means the disclosure letter provided by
      Optimal to Terra concurrently with the execution of this Agreement in a
      form and with contents that is accepted by Terra;

      "Optimal Financial Statements" means the audited consolidated financial
      statements of Optimal for the fiscal year ended December 31, 2002,
      including the Optimal Balance Sheet and the notes thereto and the
      unaudited consolidated financial statements of Optimal for the nine months
      ended September 30, 2003;

      "Optimal Meeting" means the annual and special meeting of Optimal
      Shareholders, including any adjournment or postponement thereof, to be
      called and held in accordance with applicable Laws and this Agreement to
      consider, among other things, the Optimal Resolution;

      "Optimal Meeting Date" has the meaning ascribed to it in Section 2.3(a);

      "Optimal Registered Intellectual Property" means all of the Registered
      Intellectual Property owned by, or filed in the name of, Optimal or any of
      its Subsidiaries and that is material to the conduct of Optimal's
      business;

      "Optimal Resolution" means the resolution of the Optimal Shareholders to
      authorize the issue of the Optimal Shares in order to implement the
      Transaction;

      "Optimal Shareholders" means all of the holders of securities of Optimal
      entitled to vote in respect of the Optimal Resolution;

      "Optimal Shares" means the Class "A" shares in the capital of Optimal;

      "Optimal Subco" means a wholly-owned subsidiary of Optimal to be
      incorporated under the laws of Canada for the purpose of amalgamating with
      Terra pursuant to the Amalgamation Agreement;

      "OSC" means the Ontario Securities Commission;

      "Outside Date" means, subject to Section 5.4(b), May 31, 2004 or such
      later date as may be mutually agreed by the Parties;

      "Party" or "Parties" means a signatory or the signatories to this
      Agreement, respectively;


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      "Person" includes any individual, sole proprietorship, partnership, firm,
      entity, limited partnership, limited liability company, unlimited
      liability company, unincorporated association, unincorporated syndicate,
      unincorporated organization, trust, body, corporation, or Governmental
      Authority, and where the context requires any of the foregoing when they
      are acting as trustee, executor, administrator or other legal
      representative;

      "Pre-Effective Date Period" means the period from the time of the
      execution and delivery of this Agreement between the Parties and the
      closing of the Transaction on the Effective Date, subject to the earlier
      termination of this Agreement in accordance with its terms;

      "Publicly Disclosed by Optimal" means disclosed by Optimal in a public
      filing made by it with the SEC or the OSC on the EDGAR or SEDAR systems,
      respectively, from December 31, 2002 to the date hereof;

      "Publicly Disclosed by Terra" means disclosed by Terra in a public filing
      made by it with the CVMQ on the SEDAR system from March 31, 2003 to the
      date hereof;

      "Registered Intellectual Property" means all Intellectual Property that is
      the subject of an application, certificate, filing, registration or other
      document issued, filed with, or recorded by any private, state, government
      or other legal authority;

      "Regulatory Approvals" means those sanctions, rulings, consents, orders,
      exemptions, permits, waivers, agreements, certificates and other approvals
      (including the lapse, without objection, of a prescribed time under a
      statute or regulation that states that a transaction may only be
      implemented if a prescribed time lapses following the giving of notice
      without an objection being made) of any Governmental Authority, the
      failure of which to be obtained would cause the consummation of the
      Transaction to result in the contravention or breach of any Laws, as set
      out in Schedule 3.1 to this Agreement;

      "Representatives" has the meaning ascribed to it in Section 4.6(a);

      "SEC" means the United States Securities and Exchange Commission;

      "Securities Act" means the Securities Act (Quebec);

      "subsidiary" or "Subsidiary" means, with respect to a specified body
      corporate, any body corporate of which more than 50% of the outstanding
      shares ordinarily entitled to elect a majority of the board of directors
      thereof (whether or not shares of any other class or classes shall or
      might be entitled to vote upon the happening of any event or contingency)
      are at the time owned directly or indirectly by such specified body
      corporate, and shall include any body corporate, partnership, joint
      venture or other entity over which it exercises direction or control or
      which is in a like relation to a subsidiary;


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      "Superior Proposal" means any bona fide written Acquisition Proposal that,
      in the good faith determination of the board of directors of Terra after
      consultation with its financial advisors and with outside counsel, (a) is
      reasonably capable of being completed, taking into account all legal,
      financial, regulatory and other aspects of such proposal and the party
      making such proposal, and (b) would, if consummated in accordance with its
      terms, reasonably be expected to result in a transaction more favourable
      to the Terra Shareholders, from a financial point of view, than the
      Transaction;

      "Tax" and "Taxes" means, with respect to any entity, all income taxes
      (including any tax on or based upon net income, gross income, income as
      specially defined, earnings, profits or selected items of income, earnings
      or profits) and all surtaxes, capital taxes, gross receipts taxes,
      environmental taxes, sales taxes, use taxes, ad valorem taxes, value added
      taxes, land transfer taxes, transfer taxes, franchise taxes, license
      taxes, withholding taxes or other withholding obligations, payroll taxes,
      employment taxes, Canada or Quebec Pension Plan premiums, excise,
      severance, social security premiums, workers' compensation premiums,
      employment insurance or compensation premiums, stamp taxes, occupation
      taxes, premium taxes, property taxes, windfall profits taxes, alternative
      or add-on minimum taxes, goods and services tax, harmonized sales tax,
      customs duties and import and export duties or other taxes of any kind
      whatsoever, together with any interest and any penalties or additional
      amounts imposed by any taxing authority (domestic or foreign) on such
      entity or for which such entity is responsible;

      "Tax Act" means the Income Tax Act (Canada);

      "Tax Returns" means all returns, reports, claims for refund, declarations,
      statements and other documents (whether in tangible, electronic or other
      form) and including any amendments, schedules, attachments, supplements
      and exhibits thereto, made, prepared, filed or required by any
      Governmental Authority to be made, prepared or filed in respect of Taxes;

      "Terra Benefit Plans" means all plans, arrangements, agreements, programs,
      policies, practices or undertakings, whether oral or written, formal or
      informal, funded or unfunded, registered or unregistered to which Terra or
      its subsidiaries is a party or bound by or under which Terra or its
      Subsidiaries has, or will have, any liability or contingent liability,
      relating to: pension plans, insurance plans (whether insured or
      self-insured) or compensation plans with respect to any of its employees
      or former employees (or any spouses, dependants, survivors or
      beneficiaries of any such employees or former employees), directors or
      officers, individuals working on contract with Terra or its subsidiaries
      or other individuals providing services to it of a kind normally provided
      by employees or eligible dependants of such person;

      "Terra Broker Warrants" means the 186,667 broker warrants to purchase an
      aggregate of 186,667 units at an exercise price of $3.90 per unit at any
      time on or prior to December 19, 2005, each unit comprised of one Terra
      Share and one-half


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      of one common share purchase warrant, each whole common share purchase
      warrant exercisable for one Terra Share at an exercise price of $4.50 per
      share at any time on or prior to December 19, 2005;

      "Terra Documents" has the meaning given to it in Section 3.1(u);

      "Terra Intellectual Property" shall mean any Intellectual Property that is
      owned by, or licensed to, Terra and its Subsidiaries and that is material
      to the conduct of Terra's business;

      "Terra Meeting" means the special meeting of Terra Shareholders, including
      any adjournment or postponement thereof, to be called and held to consider
      the Terra Resolution;

      "Terra Meeting Date" has the meaning given to it in Section 2.2(a);

      "Terra Options" means the options granted under the Terra Stock Option
      Plan to purchase Terra Shares;

      "Terra Registered Intellectual Property" means all of the Registered
      Intellectual Property owned by, or filed in the name of, Terra or any of
      its Subsidiaries and that is material to the conduct of Terra's business;

      "Terra Resolution" means the special resolution of the Terra Shareholders,
      approving the Amalgamation in form and content satisfactory to the
      Parties, acting reasonably;

      "Terra Shareholders" means holders of Terra Shares;

      "Terra Shares" means the common shares in the capital of Terra;

      "Terra Stock Option Plan" means the Stock Option Plan of Terra, as amended
      to the date hereof;

      "Terra Warrants" means the 1,333,334 share purchase warrants to purchase
      an aggregate of 1,333,334 Terra Shares at an exercise price of $4.50 per
      share at any time on or prior to December 19, 2005 and the 93,333 common
      share purchase warrants underlying the Terra Broker Warrants;

      "Transaction" has the meaning ascribed to it in the Recitals to this
      Agreement; and

      "TSX" means The Toronto Stock Exchange Inc.

1.2   Certain Rules of Interpretation

      In this Agreement:


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      (a)   Consent - Whenever a provision of this Agreement requires an
            approval or consent, such approval or consent shall be provided in
            writing and if such approval or consent is not delivered within the
            applicable time limit, then, unless otherwise specified, the Party
            whose consent or approval is required shall be conclusively deemed
            to have withheld its approval or consent. Unless otherwise
            specified, whenever a provision of this Agreement requires an
            approval or consent, such consent or approval shall not be
            unreasonably withheld by the Party that is requested to provide it.

      (b)   Currency - Unless otherwise specified, all references to money
            amounts are to lawful currency of Canada.

      (c)   Governing Law - This Agreement is a contract made under and shall be
            governed by and construed in accordance with the laws of the
            Province of Quebec and the federal laws of Canada applicable in the
            Province of Quebec.

      (d)   Headings - Headings of Articles and Sections are inserted for
            convenience of reference only and shall not affect the construction
            or interpretation of this Agreement.

      (e)   Including - Where the word "including" or "includes" is used in this
            Agreement, it means "including (or includes) without limitation".

      (f)   No Strict Construction - The language used in this Agreement is the
            language chosen by the Parties to express their mutual intent, and
            no rule of strict construction shall be applied against any Party.

      (g)   Number and Gender - Unless the context otherwise requires, words
            importing the singular include the plural and vice versa and words
            importing gender include all genders.

      (h)   Severability - If, in any jurisdiction, any provision of this
            Agreement or its application to any Party or circumstance is
            restricted, prohibited or unenforceable, such provision shall, as to
            such jurisdiction, be ineffective only to the extent of such
            restriction, prohibition or unenforceability without invalidating
            the remaining provisions of this Agreement and without affecting the
            validity or enforceability of such provision in any other
            jurisdiction or without affecting its application to the other Party
            or other circumstances.

      (i)   Statutory references - A reference to a statute includes all rules
            and regulations made pursuant to such statute and, unless otherwise
            specified, the provisions of any statute or regulation or rule which
            amends, supplements or supersedes any such statute or any such
            regulation or rule.

      (j)   Time - Time is of the essence in the performance of the Parties'
            respective obligations.


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      (k)   Time Periods - Unless otherwise specified, time periods within or
            following which any payment is to be made or act is to be done shall
            be calculated by excluding the day on which the period commences and
            including the day on which the period ends and by extending the
            period to the next Business Day following if the last day of the
            period is not a Business Day.

      (l)   Subsidiaries - To the extent any covenants or agreements contained
            in this Agreement relate, directly or indirectly, to a Subsidiary of
            any Party, each such provision shall be construed as a covenant by
            such Party to cause (to the fullest extent to which it is legally
            capable) such Subsidiary to perform the required action.

1.3   Entire Agreement

      This Agreement, together with the agreements and other documents required
to be delivered pursuant to this Agreement, constitutes the entire agreement
between the Parties and sets out all the covenants, promises, warranties,
representations, conditions, understandings and agreements between the Parties
pertaining to the subject matter of this Agreement and supersedes all prior
agreements, understandings, negotiations and discussions, whether oral or
written, it being understood that the Confidentiality Agreement (except for
sections 13 and 14 thereof) shall continue in full force and effect until the
closing of the transactions contemplated hereby and shall survive any
termination of this Agreement. No reliance has been made upon, and there are no
covenants, promises, warranties, representations, conditions, understandings or
other agreements, oral or written, between the Parties in connection with the
subject matter of this Agreement except as specifically set forth in this
Agreement and any document required to be delivered pursuant to this Agreement.

1.4   Schedule

      The schedule to this Agreement, as listed below, is an integral part of
this Agreement:

      Schedule          Description
      --------          -----------
      3.1               Regulatory Approvals

1.5   Accounting Matters

      Unless otherwise stated, all accounting terms used in this Agreement in
respect of any Party shall have the meanings attributable thereto under Canadian
generally accepted accounting principles and all determinations of an accounting
nature in respect of any Party required to be made shall be made in a manner
consistent with Canadian generally accepted accounting principles and such
Party's past practice.


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1.6   Knowledge

      (a)   Any reference to the knowledge of Optimal shall mean to the best of
            the knowledge, information and belief of the persons listed in the
            Optimal Disclosure Letter after reviewing all relevant records and
            making reasonable inquiries regarding the relevant matter of their
            direct reports.

      (b)   Any reference to the knowledge of Terra shall mean to the best of
            the knowledge, information and belief of the persons listed in the
            Disclosure Letter after reviewing all relevant records and making
            reasonable inquiries regarding the relevant matter of their direct
            reports.

                                    ARTICLE 2
                                 THE TRANSACTION

2.1   The Amalgamation

      Subject to the terms and conditions of this Agreement, the Parties agree
that Terra and Optimal Subco will amalgamate pursuant to the Act on the terms
and conditions set forth herein, as a result of which, among other things, each
Holder of Terra Shares will be entitled to receive the number of Optimal Shares
per Terra Share equal to the Exchange Ratio.

      2.2 Implementation Steps by Terra

      Terra covenants in favour of Optimal that Terra shall:

      (a)   subject to Section 2.4, convene and hold the Terra Meeting as soon
            as practicable after the date hereof, but in any case, before April
            30, 2004 (the "Terra Meeting Date") for the purpose of considering
            the Terra Resolution and, with the consent of Optimal, for any other
            proper purpose as may be set out in the notice for such meeting;

      (b)   subject to Section 4.5(a) and Section 5.4(b), except as required for
            quorum purposes, not postpone or cancel (or propose the adjournment,
            postponement or cancellation of) the Terra Meeting without Optimal's
            prior written consent, except as required by Law or by the Terra
            Shareholders;

      (c)   use commercially reasonable efforts to solicit from the Terra
            Shareholders proxies in favour of the approval of the Terra
            Resolution, including, if so requested by Optimal, using the
            services of dealers and proxy solicitation services and take all
            other action that is necessary or desirable to secure the approval
            of the Terra Resolution by the Terra Shareholders, except to the
            extent that the Terra board of directors has changed its
            recommendation in accordance with the terms of this Agreement; and


                                      -14-
<PAGE>

      (d)   subject to the satisfaction or waiver of the conditions herein
            contained in favour of each Party, on the date contemplated in
            Section 2.5, send to the Director, for immediate endorsement and
            filing by the Director, the Articles of Amalgamation and such other
            documents as may be required in connection therewith under the Act
            to give effect to the Transaction so that, on the Effective Date,
            Terra and Optimal Subco shall amalgamate and continue as one
            corporation under the Act on the terms and conditions set out in the
            Amalgamation Agreement.

2.3   Implementation Steps by Optimal

      Optimal covenants in favour of Terra that Optimal shall:

      (a)   subject to Section 2.4, convene and hold the Optimal Meeting as soon
            as practicable after the date hereof, but in any case, before April
            30, 2004 (the "Optimal Meeting Date") for the purpose of, among
            other things, considering the Optimal Resolution (and for any other
            proper purpose not in contravention of Section 4.3 as may be set out
            in the notice for such meeting);

      (b)   subject to Section 5.4(b), except as required for quorum purposes or
            to enable the Optimal Meeting to occur on the same day as the Terra
            Meeting, in the event that the Terra Meeting is adjourned, postponed
            or cancelled, not adjourn, postpone or cancel (or propose for
            adjournment, postponement or cancellation) the Optimal Meeting
            without Terra's prior written consent, except as required by Laws or
            by the Optimal Shareholders; and

      (c)   use commercially reasonable efforts to solicit from the Optimal
            Shareholders proxies in favour of the approval of the Optimal
            Resolution in accordance with the practices generally followed in
            Optimal's jurisdiction in similar circumstances and to take all
            other action that is necessary to secure the approval of the Optimal
            Resolution by the Optimal Shareholders, except to the extent that
            the Optimal board of directors has changed its recommendation in
            accordance with the terms of this Agreement.

2.4   Joint Proxy Circular

      As promptly as reasonably practical after the execution of this Agreement,
the Parties shall prepare and complete in consultation with each other, a joint
proxy circular concerning the Transaction (the "Joint Circular"). As promptly as
reasonably practicable thereafter, subject to obtaining any required Regulatory
Approvals in connection with the mailing of the Joint Circular, each Party shall
cause such Joint Circular and other documentation required in connection with
the respective Meetings to be mailed to their respective securityholders in
connection with the Meetings, and filed in all jurisdictions where the same is
required, all in accordance with Laws. Each Party, to


                                      -15-
<PAGE>

the extent required, shall also, as soon as reasonably practicable in
consultation with the other Party, prepare, mail and file any unique materials
required in connection with each Party's respective Meeting.

2.5   Closing Matters

      The Effective Date shall be the third Business Day following the later of
the Optimal Meeting Date, the Terra Meeting Date and the date upon which the
last Regulatory Approval is obtained, or such later date as the Parties may
agree in writing. Closing shall take place at the offices of Osler, Hoskin &
Harcourt LLP, 1000 de La Gauchetiere Street West, Suite 2100, Montreal, Quebec
H3B 4W5 at 9:00 a.m. on the Effective Date (the "Effective Time") or at such
other place, date and time as the Parties shall agree. Each of Optimal and Terra
shall deliver, at the closing of the Transaction, such customary certificates,
resolutions and other customary closing documents as may be required by the
other Party, acting reasonably.

2.6   Securities Compliance

      Optimal shall use commercially reasonable efforts to obtain all orders, if
any, required from applicable Canadian and United States securities regulatory
authorities to permit the offer, sale and issuance of the Optimal Shares to be
issued pursuant to the Transaction and to be issued upon exercise of the New
Terra Options and to permit the resale of such Optimal Shares over NASDAQ or
otherwise in the United States, without any hold period (subject to compliance
with section 4(4) of the 1933 Act), qualification with or approval of or the
filing of any prospectus, or the taking of any proceeding with, or the obtaining
of any further order, ruling or consent from, any Governmental Authority under
any United States or Canadian federal, state, provincial or territorial
securities or other United States or Canadian Laws or pursuant to the rules and
regulations of any regulatory authority administering such United States or
Canadian Laws, or the fulfilment of any other legal requirement in the United
States or any such Canadian jurisdiction (other than, with respect to such
resale, any restrictions on transfer by reason of a holder being a "control
person" of Optimal for purposes of Canadian federal, provincial or territorial
securities Laws or similar Laws in the United States).

2.7   Preparation of Filings, etc.

      (a)   Each of Optimal and Terra shall furnish to the other all information
            that may be required under Law to be provided concerning such Party
            and its shareholders for the Joint Circular and the implementation
            of the other actions described in Section 2.4 and Section 2.6. Each
            Party covenants with the other that information to be furnished by
            it (to its knowledge in the case of information concerning its
            shareholders) in connection with the Joint Circular, actions or
            otherwise in connection with the consummation of the Transaction
            will not contain any untrue statement of a material fact or omit to
            state a material fact required to be stated in any such document


                                      -16-
<PAGE>

            or which is necessary in order to make any information so furnished
            for use in any such document not misleading in the light of the
            circumstances in which it is furnished.

      (b)   Optimal and Terra shall each promptly notify the other if, at any
            time before the Effective Time, it becomes aware that the Joint
            Circular, an application for an order or any other document
            described in Section 2.6 contains any untrue statement of a material
            fact or omits to state a material fact required to be stated therein
            or which is necessary to make the statements contained therein not
            misleading in light of the circumstances in which they are made, or
            that otherwise requires an amendment or supplement to the Joint
            Circular or such application or other document. In any such event,
            Optimal and Terra shall cooperate in the preparation of a supplement
            or amendment to the Joint Circular or such application or other
            document, as required and as the case may be, and, if required,
            shall cause the same to be distributed to shareholders of Optimal or
            Terra and/or filed with the relevant Governmental Authorities.

2.8   Treatment of Stock Option Plans and Warrants

      (a)   Each Terra Option granted prior to the Effective Time that remains
            outstanding immediately prior to the Effective Time shall cease to
            represent a right to acquire Terra Shares and as at and from the
            Effective Time shall represent an option (a "New Terra Option") to
            acquire, on the same terms and conditions as were applicable under
            the Terra Option that number of Optimal Shares determined by
            multiplying the number of Terra Shares subject to the Terra Option
            by the Exchange Ratio, rounded to the nearest whole Optimal Share,
            at a price per Optimal Share equal to the Terra Option per share
            exercise price divided by the Exchange Ratio (rounded off to the
            nearest cent);

      (b)   From and after the Effective Time, the Terra Warrants, the Terra
            Broker Warrants, the EBS Warrant and the AOL Warrant shall cease to
            represent a right to acquire Terra Shares and shall represent a
            warrant to acquire, on the same terms and conditions as were
            applicable under such warrants that number of Optimal Shares
            determined by multiplying the number of Terra Shares subject to the
            Terra Warrants, the Terra Broker Warrants, the EBS Warrant and the
            AOL Warrant, as the case may be, by the Exchange Ratio (rounded to
            the nearest whole Optimal Share other than in respect of the EBS
            Warrant which shall be dealt with accordance with section 2.6
            thereof) at a price per Optimal Share equal to the applicable per
            share exercise price divided by the Exchange Ratio (rounded off to
            the nearest cent);

      (c)   Prior to the Effective Date and conditional upon the consummation of
            the Transaction, Terra shall grant to certain of its employees Terra
            Options to acquire in the aggregate 1,289,720 Terra Shares on the
            terms and


                                      -17-
<PAGE>

            conditions set out in the Disclosure Letter. The allocation of such
            Terra Options among Terra employees shall be determined by mutual
            agreement of Terra and Optimal, acting reasonably;

      (d)   Prior to the Effective Date, the employees of Terra listed in the
            Disclosure Letter shall have agreed to waive acceleration of the
            vesting of the Terra Options held by them which results from the
            completion of the Transaction, and shall have agreed that all Terra
            Options held by them, whether or not then vested, will vest on the
            same dates and in the same proportions as the first options issued
            to any senior officer of Optimal following the date of this
            Agreement.

      (e)   As soon as practicable after the Effective Time, Optimal shall
            deliver or cause to be delivered to the holders of New Terra
            Options, Terra Warrants, Terra Broker Warrants, the EBS Warrant and
            the AOL Warrant appropriate notices setting forth such holders'
            rights pursuant to the Terra Stock Option Plan and such other
            options and warrants, and agreements evidencing the New Terra
            Options and such other amended options and warrants as altered in
            accordance with Section 2.8(a) and Section 2.8(b) and stating that
            such New Terra Options and other options and warrants have been
            assumed by Optimal and shall continue in effect on the same terms
            and conditions (subject to the adjustments required by this Section
            2.8); and

      (f)   No later than five Business Days from the Effective Date, Optimal
            shall either amend its registration on Form S-8 filed with the SEC
            or file a new registration statement on Form S-8 with the SEC with
            respect to the Optimal Shares issuable upon the exercise of New
            Terra Options and shall maintain the effectiveness of such
            registration statement for so long as the New Terra Options remain
            outstanding.

                                    ARTICLE 3
                         REPRESENTATIONS AND WARRANTIES

3.1   Representations and Warranties of Terra

      Terra represents and warrants to and in favour of Optimal as follows and
acknowledges that Optimal is relying upon such representations and warranties in
connection with the matters contemplated by this Agreement:

      (a)   Organization. Each of Terra and its Subsidiaries has been duly
            incorporated or formed under the laws of its respective jurisdiction
            of incorporation, is validly existing and has all necessary
            corporate or legal power, authority, and capacity to own its
            property and assets and to carry on its business as currently owned
            and conducted. Except as set out in the Disclosure Letter, all
            Subsidiaries are wholly owned, directly or indirectly, by Terra.
            Except as set out in the Disclosure Letter, all of the outstanding


                                      -18-
<PAGE>

            shares and other ownership interests of its Subsidiaries which are
            held directly or indirectly by Terra are validly issued, fully paid
            and non-assessable, and except as set forth in the Disclosure Letter
            or for encumbrances in connection with security granted by Terra to
            its lenders in the ordinary course of business which are not in
            default, all such shares and other ownership interests are owned
            directly or indirectly by Terra, free and clear of all material
            liens, claims or encumbrances. There are no outstanding options,
            rights, entitlements, understandings or commitments (contingent or
            otherwise) regarding the right to acquire any such shares or other
            ownership interests in any of Terra's Subsidiaries. The Disclosure
            Letter sets out the names and jurisdictions of incorporation of each
            of Terra's Subsidiaries.

      (b)   Capitalization. The authorized capital of Terra consists of an
            unlimited number of Terra Shares and an unlimited number of
            preferred shares. As of the date hereof, there are 15,978,216 Terra
            Shares (and no more) and no preferred shares issued and outstanding.
            In addition, as at the date hereof, options to acquire an aggregate
            of not more than 995,045 Terra Shares have been granted and are
            outstanding under the Terra Stock Option Plan, 1,613,334 Terra
            Shares may be issued upon the exercise of the Terra Warrants, 50,000
            Terra Shares may be issued upon the exercise of the AOL Warrant and
            up to 59,368 Terra Shares may be issued upon the exercise of the EBS
            Warrant. Except for such options, warrants and broker warrants as
            are described in the preceding sentence of this Section 3.1(b),
            there are no options, warrants, conversion privileges or other
            rights, agreements, arrangements or commitments (pre-emptive,
            contingent or otherwise) obligating Terra or any of its Subsidiaries
            to issue or sell any shares of Terra or of any such Subsidiary or
            securities or obligations of any kind convertible into or
            exchangeable for any shares of Terra or any of its Subsidiaries. All
            outstanding Terra Shares have been duly authorized and are validly
            issued and outstanding as fully paid and non-assessable shares, free
            of pre-emptive rights. There are no outstanding bonds, debentures or
            other evidences of indebtedness of Terra or any of its Subsidiaries
            having the right to vote (or that are convertible for or exercisable
            into securities having the right to vote) with the Holders of the
            Terra Shares on any matter. Except as set out in the Disclosure
            Letter, neither Terra nor any of its Subsidiaries have any
            obligation to repurchase, redeem or otherwise acquire any of its
            outstanding securities or with respect to the voting or disposition
            of any outstanding securities of any of Terra Subsidiaries. No
            holder of securities issued by Terra or any of its Subsidiaries has
            any right to compel Terra to register or otherwise qualify
            securities for public sale in Canada or the United States or
            elsewhere.

      (c)   Authority and No Violation.

            (i)   Terra has the necessary corporate power, authority and
                  capacity to enter into, and to perform its obligations under,
                  this Agreement.


                                      -19-
<PAGE>

                  The execution and delivery of this Agreement by Terra and the
                  consummation by Terra of the transactions contemplated by this
                  Agreement have been duly authorized by its board of directors
                  and no other corporate proceedings on its part are necessary
                  to authorize this Agreement or the transactions contemplated
                  under this Agreement, other than:

                  (A)   with respect to the Joint Circular and other matters
                        relating solely thereto, the approval of the board of
                        directors of Terra; and

                  (B)   with respect to the completion of the Amalgamation, the
                        approval of the Terra Shareholders as described in
                        Article 2.

            (ii)  This Agreement has been duly executed and delivered by Terra
                  and constitutes a legal, valid and binding obligation of
                  Terra, enforceable against Terra in accordance with its terms,
                  subject to bankruptcy, insolvency and other applicable Laws
                  affecting creditors' rights generally, and to general
                  principles of equity.

            (iii) The board of directors of Terra has (A) unanimously determined
                  as of the date hereof that the Transaction is fair to the
                  Terra Shareholders and is in the best interest of Terra, (B)
                  received a written opinion of Terra's financial advisor,
                  McColl Partners, LLC, rendered to the board of directors of
                  Terra and dated the date of this Agreement that, as of the
                  date of the opinion and based upon and subject to the various
                  assumptions and limitations set forth in the opinion, the
                  Exchange Ratio for the Optimal Shares proposed to be received
                  by the Terra Shareholders in exchange for their Terra Shares
                  in connection with the Transaction is fair to Terra
                  Shareholders from a financial point of view and (C) determined
                  as of the date hereof to unanimously recommend that the Terra
                  Shareholders vote in favour of the Terra Resolution. Terra's
                  directors have advised Terra that they intend to vote Terra
                  Shares held by them in favour of the Terra Resolution and will
                  so represent in the Joint Circular.

            (iv)  The authorization of this Agreement, the execution and
                  delivery by Terra of this Agreement and the performance by it
                  of its obligations hereunder and the completion of the
                  Transaction will not, except as set out in the Disclosure
                  Letter:

                  (A)   result (with or without notice or the passage of time)
                        in a violation or breach of, or constitute a default
                        under, require any consent to be obtained under or give
                        rise to any third party right of termination,
                        cancellation, acceleration,


                                      -20-
<PAGE>

                        penalty or payment obligation or right of purchase or
                        sale under, any provision of:

                        A.    Terra's or any of its Subsidiaries' certificate of
                              incorporation, articles, by-laws or other charter
                              documents or any agreement with a shareholder;

                        B.    any Laws (subject to obtaining the Regulatory
                              Approvals), except to the extent that the
                              violation or breach of, or failure to obtain any
                              consent would not, individually or in the
                              aggregate, reasonably be expected to prevent or
                              delay the Transaction or have a Material Adverse
                              Effect on Terra; or

                        C.    any Contract, licence, permit or government grant
                              to which Terra or any of its Subsidiaries is party
                              or by which it is bound, except as would not,
                              individually or in the aggregate, reasonably be
                              expected to prevent or delay the Transaction or
                              have a Material Adverse Effect on Terra;

                  (B)   give rise to any right of termination or acceleration of
                        indebtedness of Terra or any of its Subsidiaries, or
                        cause any such indebtedness to come due before its
                        stated maturity, or cause any available credit of Terra
                        or any of its Subsidiaries to cease to be available,
                        except as would not, individually or in the aggregate,
                        reasonably be expected to prevent or delay the
                        Transaction or have a Material Adverse Effect on Terra;

                  (C)   result in the imposition of any encumbrance, charge or
                        lien upon any of Terra's assets or the assets of any of
                        its Subsidiaries, except as would not, individually or
                        in the aggregate, reasonably be expected to prevent or
                        delay the Transaction or have a Material Adverse Effect
                        on Terra;

                  (D)   restrict, hinder, impair or limit the ability of Terra
                        or any of its Subsidiaries to carry on the business of
                        Terra or any of its Subsidiaries as and where it is now
                        being carried on, except as would not, individually or
                        in the aggregate, reasonably be expected to prevent or
                        delay the Transaction or have a Material Adverse Effect
                        on Terra; or

                  (E)   result in any payment (including retention, severance,
                        unemployment compensation, golden parachute, bonus or
                        otherwise) becoming due to any director, officer or
                        employee of Terra or any of its Subsidiaries or increase
                        any


                                      -21-
<PAGE>

                        benefits otherwise payable under any Terra Benefit Plan
                        or result in the acceleration of time of payment or
                        vesting of any such benefits, including the time of
                        exercise of stock options.

            (v)   No consent, approval, order or authorization of, or
                  declaration or filing with, any Governmental Authority is
                  required to be obtained by Terra and its Subsidiaries in
                  connection with the execution and delivery of this Agreement
                  or the consummation by Terra of the Transaction other than (A)
                  filings under the Act contemplated by this Agreement, (B) the
                  Regulatory Approvals relating to Terra, (C) filings under the
                  Securities Act, stock exchange rules and similar Laws as
                  contemplated by this Agreement or to provide notice of the
                  Transaction and (D) any other consents, approvals, orders,
                  authorizations, declarations or filings of or with a
                  Governmental Authority which, if not obtained, could not,
                  individually or in the aggregate, reasonably be expected to
                  prevent or delay the Transaction or have a material affect on
                  Terra.

      (d)   Financial Statements. The Financial Statements have been prepared in
            accordance with generally accepted accounting principles in Canada
            and applicable Laws. Such Financial Statements present fairly, in
            all material respects, the consolidated financial position and
            results of operations of Terra as of the respective dates thereof
            and for the respective periods covered thereby applied on a basis
            consistent with the immediately prior period and throughout the
            periods indicated (except as may be indicated expressly in the notes
            thereto) and in the case of unaudited statements, to normal,
            recurring year-end adjustments and the absence of notes applicable
            to audited year-end financial statements. Such Financial Statements
            reflect appropriate and adequate reserves in respect of contingent
            liabilities, if any, of Terra and its Subsidiaries on a consolidated
            basis.

      (e)   Indebtedness for Borrowed Money and Contingent Liabilities. Except
            as set forth in the Disclosure Letter, or as Publicly Disclosed by
            Terra, or for liabilities and obligations incurred in the ordinary
            course of business consistent with past practice since the date of
            the Balance Sheet, neither Terra nor any of its Subsidiaries has any
            liabilities or obligations of any nature (whether accrued, absolute,
            contingent or otherwise) except for those that could not, in the
            aggregate, reasonably be expected to have a Material Adverse Effect
            on Terra. Neither Terra or any of its Subsidiaries has any
            indebtedness for borrowed money.

      (f)   Absence of Certain Changes or Events. Except as set out in the
            Disclosure Letter or as Publicly Disclosed by Terra, since the date
            of the Balance Sheet each of Terra and its Subsidiaries has
            conducted its business only in


                                      -22-
<PAGE>

            the ordinary course of business consistent with past practice and
            there has not occurred:

            (i)   a Material Adverse Change with respect to Terra or any
                  circumstances or events that could individually or in the
                  aggregate, reasonably be expected to give rise to a Material
                  Adverse Change with respect to Terra;

            (ii)  any material damage, destruction or loss not fully covered by
                  insurance;

            (iii) any redemption, repurchase or other acquisition of Terra
                  Shares by Terra or Terra Benefits Plans, or any declaration,
                  setting aside or payment of any dividend or other distribution
                  (whether in cash, shares or property) with respect to Terra
                  Shares;

            (iv)  any increase in or modification of the compensation payable or
                  to become payable by it to any of its directors or officers,
                  or any grant to any director, officer or employee of any
                  increase in entitlements under, or general institution of,
                  retention, severance or termination programs or pay other than
                  annual increases consistent with past practice or as a result
                  of promotions in the ordinary course of business;

            (v)   any increase in or modification of any bonus, pension,
                  retention, insurance or benefit arrangement (including the
                  granting of stock options, restricted stock awards or stock
                  appreciation rights) made to, for or with any of such
                  directors, officers or employees other than annual increases
                  consistent with past practice, as required under Law or as a
                  result of promotions in the ordinary course of business;

            (vi)  any acquisition or sale by it of any material asset(s) or
                  investment except in the ordinary course of business with
                  Subsidiaries or Arm's Length Persons consistent with past
                  practice;

            (vii) a material change in the level of its accounts receivable or
                  payable, or employees other than in the ordinary course;

           (viii) any entering into by it, or an amendment by it of, any
                  material Contract other than in the ordinary course of
                  business with subsidiaries or Arm's Length Persons consistent
                  with past practice;

            (ix)  relinquishment, termination or non-renewal by it of any
                  material Contracts;

            (x)   any creation or assumption by it of any hypothec, mortgage,
                  pledge, security interest or lien or other encumbrance on any
                  asset


                                      -23-
<PAGE>

                  except to Arm's Length Persons in the ordinary course of
                  business consistent with past practice;

            (xi)  any resolution to approve a split, consolidation or
                  reclassification of any of its outstanding shares;

            (xii) any change in its accounting methods, policies or practices or
                  revaluation of assets;

           (xiii) any guarantee by it of the payment of material indebtedness
                  or any incurrence by it of material indebtedness for money
                  borrowed or any issue or sale by it of any debt securities or
                  securities convertible or exchangeable for debt securities;

            (xiv) any satisfaction or settlement by it of any material claims or
                  liabilities that were not reflected in the Balance Sheet,
                  other than settlement of liabilities incurred in the ordinary
                  course of business with Arm's Length Persons consistent with
                  past practice;

            (xv)  any entering into by it into any licensing or other agreement
                  with regard to the acquisition or disposition of any
                  Intellectual Property other than licenses in the ordinary
                  cause of business consistent with past practice; or

            (xvi) any agreement by it to do any of the foregoing.

      (g)   Books and Records. The financial books, records and accounts of
            Terra and its Subsidiaries, in all material respects, (i) have been
            maintained in accordance with accounting principles generally
            accepted in Canada on a basis consistent with prior periods, (ii)
            are stated in reasonable detail and accurately and fairly reflect
            the material transactions and dispositions of the assets of Terra
            and its Subsidiaries and (iii) accurately and fairly reflect the
            basis for the Financial Statements. Terra has devised and maintains
            a system of internal accounting controls sufficient to provide
            reasonable assurances that (i) transactions are executed in
            accordance with management's general or specific authorization; and
            (ii) transactions are recorded as necessary (A) to permit
            preparation of financial statements in conformity with Canadian
            generally accepted accounting principles, or any other criteria
            applicable to such statements and (B) to maintain accountability for
            assets. Except as set out in the Terra Disclosure Letter, Terra's
            corporate minute books contain minutes of all meetings and
            resolutions of the directors and Terra Shareholders held, and full
            access thereto has been provided to Optimal with the exception of
            minutes relating to the Transaction.

      (h)   No Defaults. Except as set out in the Terra Disclosure Letter,
            neither Terra nor any of its Subsidiaries is in default under, and
            there exists no event,


                                      -24-
<PAGE>

            condition or occurrence which, after notice or lapse of time or
            both, would constitute such a default under any material Contract;

      (i)   Customers and Suppliers. There is no single customer or supplier of
            Terra or its Subsidiaries, the loss of which would be material to
            Terra. Since September 30, 2003, there has been no termination or
            cancellation of, and no material adverse modification or change in,
            the business relationship with any customer or group of customers
            which individually or in the aggregate provided more than 5% of the
            consolidated gross revenues of Terra and its Subsidiaries for the
            twelve months ended December 31, 2003.

      (j)   Litigation. Except as set out in the Disclosure Letter or Publicly
            Disclosed by Terra: (i) as of the date hereof, there is no claim,
            action, proceeding or investigation that has been commenced or, to
            the knowledge of Terra, threatened against Terra or any of its
            Subsidiaries before any Governmental Authority and, at the Effective
            Time, there will be no claim, action, proceeding or investigation
            that will have been commenced or, to the knowledge of Terra,
            threatened against Terra or any of its Subsidiaries before any
            Governmental Authority, that, if adversely determined, could
            reasonably be expected to have a Material Adverse Effect on Terra or
            prevent or delay consummation of the Transaction; (ii) neither Terra
            nor any of its Subsidiaries, nor any of their respective assets and
            properties, is subject to any outstanding judgment, order, writ,
            injunction or decree that has had or is reasonably likely to have a
            Material Adverse Effect on Terra or prevent or delay consummation of
            the Transaction; and (iii) neither Terra nor any of its Subsidiaries
            is subject to any material warranty, negligence, performance or
            other claims or disputes or potential claims or disputes in respect
            of products or services currently being delivered or previously
            delivered, and to the knowledge of Terra there are no events or
            circumstances which could reasonably be expected to give rise to any
            such claims or disputes or potential claims or disputes;

      (k)   Restrictions on Business Activities. Except as set out in the
            Disclosure Letter, there is no agreement, judgment, injunction,
            order or decree binding upon Terra or any of its Subsidiaries that
            has or could reasonably be expected to have the effect of
            prohibiting, restricting or materially impairing any material
            business practice of Terra or any of its Subsidiaries, any
            acquisition of property by Terra or any of its Subsidiaries or the
            conduct of business by Terra or any of its Subsidiaries as currently
            conducted (including following the Transaction).

      (l)   Intellectual Property.

            (i)   The Disclosure Letter contains a complete and accurate list of
                  all Terra Registered Intellectual Property and specifies,
                  where applicable, the jurisdictions in which each such item of
                  Terra


                                      -25-
<PAGE>

                  Registered Intellectual Property has been filed, applied for,
                  issued or registered and lists any proceedings or actions
                  before any court or tribunal (including the United States
                  Patent and Trademark Office or equivalent authority anywhere
                  in the world) related to any Terra Registered Intellectual
                  Property. All items of Terra Registered Intellectual Property
                  have been properly maintained and, where applicable, renewed
                  in accordance with the Laws of the jurisdictions in which such
                  registration of intellectual property were made, except where
                  the failure to maintain and renew the Terra Registered
                  Intellectual Property could not reasonably be expected to have
                  a Material Adverse Effect on Terra.

            (ii)  No Terra Intellectual Property is subject to any proceeding or
                  outstanding decree, order, judgment, contract, license,
                  agreement, or stipulation restricting in any manner the use,
                  transfer, or licensing thereof by Terra or any of its
                  Subsidiaries, or which may affect the validity, use or
                  enforceability of such Terra Intellectual Property.

            (iii) Terra owns and has good and exclusive title to, each material
                  item of Terra Intellectual Property owned by it free and clear
                  of any lien or encumbrance (excluding non-exclusive licenses
                  and related restrictions granted in the ordinary course). All
                  Intellectual Property necessary for or used in the business of
                  Terra and its Subsidiaries which is not Terra Intellectual
                  Property is used by Terra and its Subsidiaries with the
                  consent of or license from the rightful owner thereof.

            (iv)  Except as set out in the Disclosure Letter, neither Terra nor
                  any of its Subsidiaries has transferred ownership of, or
                  granted any license with respect to, any Intellectual Property
                  that is Terra Intellectual Property, to any third party. All
                  Terra Intellectual Property is in full force and effect and
                  has not been used or enforced or failed to have been used or
                  enforced in a manner that would result in abandonment,
                  cancellation or unenforceability of any Terra Intellectual
                  Property.

            (v)   The Disclosure Letter lists all material contracts, licenses
                  and agreements to which Terra or any of its Subsidiaries is a
                  party: (A) with respect to Terra Intellectual Property
                  licensed or transferred to any third party (other than
                  end-user licenses in the ordinary course); or (B) pursuant to
                  which a third party has licensed or transferred any material
                  Intellectual Property to Terra.

            (vi)  All material contracts, licenses and agreements relating to
                  either (A) Terra Intellectual Property or (B) Intellectual
                  Property of a third party licensed to Terra or any of its
                  Subsidiaries, are in full


                                      -26-
<PAGE>

                  force and effect. Except as disclosed in the Disclosure
                  Letter, the Transaction will neither violate nor result in the
                  breach, modification, cancellation, termination or suspension
                  of such contracts, licenses and agreements. Each of Terra and
                  its Subsidiaries is in material compliance with, and has not
                  materially breached any term of, such contracts, licenses and
                  agreements and, to the knowledge of Terra, all other parties
                  to such contracts, licenses and agreements are in compliance
                  with, and have not materially breached any term of, such
                  contracts, licenses and agreements. Following the Effective
                  Date, Terra will be permitted to exercise all of its rights
                  under such contracts, licenses and agreements to the same
                  extent it and its Subsidiaries would have been able to had the
                  transactions contemplated by this Agreement not occurred and
                  without the payment of any additional amounts or consideration
                  other than ongoing fees, royalties or payments which it would
                  otherwise be required to pay. Neither this Agreement nor the
                  transactions contemplated by this Agreement, will result in
                  (A) Terra granting to any third party any right to or with
                  respect to any material Intellectual Property right owned by,
                  or licensed to it, (B) Terra being bound by, or subject to,
                  any non-compete or other material restriction on the operation
                  or scope of its business, or (C) Terra being obligated to pay
                  any royalties or other material amounts to any third party in
                  excess of those payable by Terra, prior to the Effective Date.

            (vii) Except as set out in the Disclosure Letter, the operation of
                  the business of Terra and its Subsidiaries as such business
                  currently is conducted, including (A) Terra's and its
                  Subsidiaries' design, development, manufacture, distribution,
                  reproduction, marketing or sale of the products or services of
                  Terra and its Subsidiaries and (B) Terra's use of any product,
                  device or process, has not, does not and, to its knowledge,
                  will not infringe or misappropriate the Intellectual Property
                  of any third party or constitute unfair competition or trade
                  practises under the laws of any jurisdiction.

           (viii) Except as set out in the Disclosure Letter, neither Terra nor
                  any of its Subsidiaries has received notice from any third
                  party that the operation of the business of Terra or any of
                  its Subsidiaries or any act, product or service of Terra or
                  any of its Subsidiaries, infringes or misappropriates the
                  Intellectual Property of any third party or constitutes unfair
                  competition or trade practises under the laws of any
                  jurisdiction.

            (ix)  To the knowledge of Terra, no Person has or is infringing or
                  misappropriating any Terra Intellectual Property. Terra has
                  not commenced legal proceedings relating to an infringement by
                  any Person of Terra Intellectual Property.


                                      -27-
<PAGE>

            (x)   Terra and each of its Subsidiaries has taken reasonable steps
                  to protect Terra's and its Subsidiaries' rights in Terra's
                  confidential information and trade secrets that it wishes to
                  protect or any trade secrets or confidential information of
                  third parties provided to Terra or any of its Subsidiaries,
                  and, without limiting the foregoing, each of Terra and its
                  Subsidiaries has enforced and currently enforces a policy
                  requiring each employee and contractor to execute a
                  proprietary information/confidentiality agreement
                  substantially in the form provided to Optimal and all current
                  and former employees and contractors of Terra and any of its
                  Subsidiaries have executed such an agreement, except where the
                  failure to do so could not reasonably be expected to have a
                  Material Adverse Effect on Terra.

      (m)   Employment Matters.

            (i)   Terra has provided Optimal with a true and complete list of
                  all employees of Terra and its Subsidiaries as of the date
                  hereof, including details regarding compensation.

            (ii)  Except as set out in the Disclosure Letter or as Publicly
                  Disclosed by Terra, neither Terra nor any of its Subsidiaries
                  is a party to any agreement, obligation or understanding
                  providing for severance or termination payments to any of
                  their directors, officers or employees, other than any
                  obligations of reasonable notice of termination or pay in lieu
                  thereof under applicable Laws.

            (iii) Neither Terra nor any of its Subsidiaries is subject to any
                  collective bargaining agreements, or subject to any
                  application or threatened or apparent union organizing
                  campaigns for employees not under a collective bargaining
                  agreement, nor are there any current, pending or, to the
                  knowledge of Terra, threatened strikes, work stoppages or
                  lockouts at Terra or any of its Subsidiaries.

      (n)   Pension and Employee Benefits.

            Except as set out in the Disclosure Letter:

            (i)   The Terra Benefit Plans comply in all material respects with
                  all applicable Laws and such plans have been administered in
                  compliance with applicable Laws and their terms;

            (ii)  All of the Terra Benefit Plans that are pension plans are
                  either (A) fully insured or (B) fully funded in accordance
                  with applicable Laws on a going concern solvency basis and
                  winding-up solvency basis. Neither Terra nor any of its
                  Subsidiaries has received, or applied for, any payment of
                  surplus out of any Terra Benefit Plan or any payment in
                  respect of the demutualization of an insurer.


                                      -28-
<PAGE>

                  Neither Terra nor its Subsidiaries has taken any contribution
                  or premium holidays under any Terra Benefit Plan except as
                  permitted by applicable Laws and the terms of the Terra
                  Benefit Plan;

            (iii) None of the Terra Benefit Plans, other than pension plans
                  which only provide monetary retirement payments in accordance
                  with the terms of such plans, provides benefits beyond
                  retirement or other termination of service to employees or
                  former employees or to the beneficiaries or dependants of such
                  employees, or such benefits have been properly accrued on the
                  Financial Statements in accordance with generally accepted
                  accounting principles;

            (iv)  No event has occurred and no condition or circumstance exists
                  that has resulted in or could reasonably be expected to result
                  in any Terra Benefit Plan being ordered, or required to be,
                  terminated or wound up in whole or in part, having its
                  registration under applicable Laws refused or revoked, being
                  placed under the administration of any trustee or receiver or
                  regulatory authority or being required to pay any material
                  Taxes, penalties, payments or levies under applicable Laws;

            (v)   There are no outstanding stock appreciation rights, phantom
                  equity, profit saving plan or similar rights, agreements,
                  arrangements or commitments payable to directors, officers or
                  employees based upon the revenue, value, income or any other
                  attribute of Terra or any of its Subsidiaries; and

            (vi)  None of the Terra Benefit Plans is subject to the provisions
                  of Title I of the U.S. Employee Retirement Income Security Act
                  of 1974, as amended.

      (o)   Tax Matters. Except as set out in the Disclosure Letter:

            (i)   Terra and each of its Subsidiaries have filed, or caused to be
                  filed, all Tax Returns required to be filed by them in the
                  form and within the time prescribed under applicable Laws for
                  so doing (all of which Tax Returns were true and complete).
                  Terra and each of its Subsidiaries have duly and timely paid,
                  collected, withheld and remitted all Taxes (including all
                  instalments on account of Taxes) each of them is required to
                  pay, collect, withhold or remit (respectively) and the
                  Financial Statements contain an adequate provision in
                  accordance with Canadian generally accepted accounting
                  principles for all material amounts of Taxes payable in
                  respect of each period covered by such Financial Statements
                  and all prior periods to the extent such Taxes have not been
                  paid, whether or not due and whether or not shown as being due
                  on any


                                      -29-
<PAGE>

                  Tax Returns. On a consolidated basis, Terra has made adequate
                  provision in accordance with generally accepted accounting
                  principles in its books and records for any material amounts
                  of Taxes accruing in respect of any accounting period which
                  has ended subsequent to the period covered by such Financial
                  Statements;

            (ii)  All Tax Returns of Terra and its Subsidiaries have been
                  assessed and all deficiencies proposed with respect to Terra
                  and its Subsidiaries as a result of such assessments or
                  reassessments of the Tax Returns have been paid or settled.
                  There are no proceedings, investigations, audits or claims now
                  pending or, to the knowledge of Terra, threatened against
                  Terra or any of its Subsidiaries in respect of any material
                  amount of Taxes and there are no matters under discussion,
                  audit or appeal with any Governmental Authority relating to a
                  material amount of Taxes. No written claim (or to the
                  knowledge of Terra, other claims) has ever been made by a
                  Governmental Authority in a jurisdiction where neither Terra
                  nor any of its Subsidiaries file Tax Returns that Terra or any
                  Subsidiary is or may be subject to taxation in that
                  jurisdiction. No Tax liens have been filed for material
                  amounts of Taxes other than for Taxes not yet due or payable.
                  Neither Terra nor any of its Subsidiaries has acquired
                  property from another person for consideration, the value of
                  which is less than the fair market value of the property
                  acquired, in circumstances which could subject Terra or a
                  Subsidiary, as applicable, to liability for any Taxes of such
                  other person who was, at the time the property was acquired, a
                  member of the same combined, affiliated, related or
                  consolidated group, or under common control with Terra or any
                  such Subsidiary (including pursuant to section 160 of the Tax
                  Act). Since December 31, 2000, none of Terra nor any of its
                  Subsidiaries has requested, offered to enter into or entered
                  into any agreement or other arrangement, or executed any
                  waiver, providing for any extension of time within which (i)
                  to file any Tax Return covering any Taxes for which Terra or
                  any of its Subsidiaries is or may be liable; (ii) to file any
                  elections, designations or similar filings relating to Taxes
                  for which Terra or any of its Subsidiaries is or may be
                  liable; or (iii) Terra or any of its Subsidiaries is required
                  to pay or remit any Taxes or amounts on account of Taxes. None
                  of Terra nor any of its Subsidiaries has requested, offered to
                  enter into or entered into any agreement or other arrangement,
                  or executed any waiver, providing for any extension of time
                  within which any Governmental Authority may assess or collect
                  Taxes for which Terra or any of its Subsidiaries is or may be
                  liable. Neither Terra nor any of its Subsidiaries is a party
                  to any tax sharing or other similar agreement or arrangement
                  of any nature with any other Person (other than Terra or any
                  of its Subsidiaries) pursuant to


                                      -30-
<PAGE>

                  which Terra or any of the Subsidiaries has or could have any
                  material liabilities in respect of Taxes, other than any
                  liability arising under an agreement providing for the sale or
                  other disposition of property by Terra or any of its
                  Subsidiaries. Neither Terra nor any of its Subsidiaries has
                  received a refund of any material amount of Taxes to which it
                  was not entitled; and

            (iii) For purposes of this Section 3.1(o), the term "material amount
                  of Taxes" shall mean an amount of Taxes that is material to
                  Terra and its Subsidiaries taken as a whole.

      (p)   Compliance with Laws. Except as set out in the Disclosure Letter,
            Terra and its Subsidiaries have complied in all material respects
            with and are not in violation of any Laws, including applicable End
            User Laws, other than non-compliance or violations which would not,
            individually or in the aggregate, reasonably be expected to have a
            Material Adverse Effect on Terra. Without limiting the generality of
            the foregoing, all securities of Terra (including, all options,
            warrants, rights or other convertible or exchangeable securities)
            have been issued in compliance with all applicable securities Laws
            and all securities to be issued upon exercise of any such options,
            warrants, rights and other convertible or exchangeable securities
            will be issued in compliance with all applicable securities Laws.

      (q)   Licences, Etc. Terra and each of its Subsidiaries owns, possesses,
            or has obtained and is in compliance with, all material licences,
            permits, certificates, orders, grants and other authorizations of or
            from any Governmental Authority necessary to conduct its business
            substantially as now conducted except where failure would not,
            individually or in the aggregate, reasonably be expected to have a
            Material Adverse Effect on Terra.

      (r)   Environmental. Except as set out in the Disclosure Letter or as
            Publicly Disclosed by Terra or for any matters that, individually or
            in the aggregate, could not reasonably be expected to have a
            Material Adverse Effect on Terra:

            (i)   all operations of Terra and its Subsidiaries have been
                  conducted and are now in compliance with all Environmental
                  Laws; and

            (ii)  neither Terra nor any of its Subsidiaries is subject to:

                  (A)   any Environmental Laws or terms of any environmental
                        authorization, permit or licence which requires or may
                        require any work, repairs, construction, change in
                        business practices or operations, or expenditures; or


                                      -31-
<PAGE>

                  (B)   any written demand, notice or order with respect to a
                        breach of or liability under any Environmental Laws
                        applicable to Terra or any of its Subsidiaries.

      (s)   Property. Neither of Terra nor any of its Subsidiaries owns any
            immovable (real) property. Neither Terra nor any of its Subsidiaries
            is in default under any lease or sublease relating to immovable
            (real) property which could give any other party the right to
            terminate the lease or sublease, as the case may be.

      (t)   Non-Arm's Length Transactions. Except as set out in the Disclosure
            Letter, there are no material Contracts or other transactions
            between Terra or any of its Subsidiaries, on the one hand, and any
            (i) officer or director of Terra or any of its Subsidiaries, (ii)
            any holder of record or beneficial owner of 5% or more of the voting
            securities of Terra, or (iii) any Affiliate or associate of any such
            officer, director or beneficial owner, on the other hand.

      (u)   Reports. Terra has filed with the CVMQ, by posting upon the SEDAR
            system, true and complete copies of all forms, reports, schedules,
            statements and other documents required in accordance with
            applicable Laws to be filed by it in the last three years. (Such
            forms, reports, schedules, statements and other documents, including
            any financial statements or other documents, including any schedules
            included therein, are referred to as the "Terra Documents".) The
            Terra Documents at the time filed (i) did not contain any
            misrepresentation of a material fact or omit to state a material
            fact required to be stated therein or necessary to make the
            statements therein, in the light of the circumstances under which
            they were made, not misleading, and (ii) complied in all material
            respects with the requirements of applicable securities Laws. Terra
            has not filed any confidential material change report with the CVMQ
            or any other securities authority or regulator or any stock exchange
            or other self-regulatory authority which at the date hereof remains
            confidential.

      (v)   Fees. The Disclosure Letter contains a true and complete list of of
            all agreements that could give rise to any claim for an advisory
            fee, success fee, brokerage commission, finder's fee or other like
            payment against Terra or any of its Subsidiaries in connection with
            the Transaction.

      (w)   Insurance. Terra has made available to Optimal a true and correct
            summary of all material policies of insurance to which each of Terra
            and its Subsidiaries are a party or a beneficiary or named insured.
            Except as set out in the Disclosure Letter, Terra and its
            Subsidiaries maintain insurance coverage with reputable insurers in
            such amounts and covering such risks as are in accordance with
            normal industry practice for companies engaged in businesses similar
            to that of Terra and its Subsidiaries.


                                      -32-
<PAGE>

      (x)   Cumulative Breach. The breaches, if any, of the representations made
            by Terra in this Agreement that would occur if all references in
            such representations to phrases concerning materiality were deleted,
            are not breaches that in the aggregate represent circumstances which
            (i) have or could reasonably be expected to have a Material Adverse
            Effect on Terra, or (ii) constitute or could reasonably be expected
            to constitute a Material Adverse Change in respect of Terra.

      (y)   Investment Canada. Terra is not a financial institution within the
            meaning of the Investment Canada Act (Canada).

      (z)   Inter-Company Guarantees. Except as set out in the Disclosure
            Letter, Terra has not guaranteed any liabilities or obligations
            (whether accrued, absolute, contingent or otherwise) of any of its
            Subsidiaries nor has any Terra Subsidiary provided any such
            guarantee for any other Terra Subsidiary.

3.2   Representations and Warranties of Optimal

      Optimal represents and warrants to and in favour of Terra as follows and
acknowledges that Terra is relying upon such representations and warranties in
connection with the matters contemplated by this Agreement:

      (a)   Organization. Each of Optimal and its Subsidiaries has been duly
            incorporated or formed under the laws of its respective jurisdiction
            of incorporation, is validly existing and has all necessary
            corporate or legal power, authority, and capacity to own its
            property and assets and to carry on its business as currently owned
            and conducted. Except as set out in the Optimal Disclosure Letter,
            all Subsidiaries of Optimal are wholly owned, directly or
            indirectly, by Optimal. All of the outstanding shares and other
            ownership interests of its Subsidiaries which are held directly or
            indirectly by Optimal are validly issued, fully paid and
            non-assessable, and except as set forth in the Optimal Disclosure
            Letter or for encumbrances in connection with security granted by
            Optimal to its lenders in the ordinary course of business which are
            not in default, all such shares and other ownership interests are
            owned directly or indirectly by Optimal, free and clear of all
            material liens, claims or encumbrances. Except as set out in the
            Optimal Disclosure Letter, there are no outstanding options, rights,
            entitlements, understandings or commitments (contingent or
            otherwise) regarding the right to acquire any such shares or other
            ownership interests in any of Optimal's Subsidiaries.

      (b)   Capitalization. Optimal has sufficient authorized capital to issue
            all of the Optimal Shares that may be required to be issued under
            the transactions contemplated by this Agreement. As of the date
            hereof, there are 14,936,235 Optimal Shares (and no more) issued and
            outstanding. In addition, as at the date hereof, options to acquire
            an aggregate of not more


                                      -33-
<PAGE>

            than 8,500 Optimal Shares have been granted and are outstanding.
            Additional options to acquire Optimal Shares may be issued by
            Optimal to directors, senior officers and employees of Optimal prior
            to the Effective Time. Other than the foregoing, there are no
            outstanding securities having the right to vote (or that are
            convertible for or exercisable into securities having the right to
            vote) with the holders of Optimal Shares on any matter. There are no
            outstanding contractual obligations of Optimal to repurchase or
            acquire any Optimal Shares. Prior to the Effective Date, additional
            Optimal Shares may be issued in consideration for cash and other
            property.

      (c)   Authority and No Violation.

            (i)   Optimal has the necessary corporate power, authority and
                  capacity to enter into this Agreement and to perform its
                  obligations under this Agreement. The execution and delivery
                  of this Agreement by Optimal and the consummation by Optimal
                  and its Subsidiaries of the transactions contemplated by this
                  Agreement have been duly authorized by its board of directors
                  and no other corporate proceedings on the part of Optimal are
                  necessary to authorize this Agreement or the transactions
                  contemplated under this Agreement, other than:

                  (A)   with respect to the Optimal Meeting, the Joint Circular
                        and other matters relating solely thereto, the approval
                        of the Optimal Board; and

                  (B)   the approval of the Optimal Shareholders described in
                        Article 2.

            (ii)  This Agreement has been duly executed and delivered by Optimal
                  and constitutes a legal, valid and binding obligation,
                  enforceable against it in accordance with its terms, subject
                  to bankruptcy, insolvency and other applicable Laws affecting
                  creditors' rights generally, and to general principles of
                  equity.

            (iii) The Optimal Board has (A) unanimously determined as of the
                  date hereof that the Transaction is in the best interests of
                  Optimal, and (B) determined as of the date hereof to
                  unanimously recommend that the Optimal Shareholders vote in
                  favour of the Optimal Resolution. Optimal's directors have
                  advised Optimal that they intend to vote Optimal Shares held
                  by them in favour of the Optimal Resolution and will so
                  represent in the Joint Circular.

            (iv)  The approval of this Agreement, the execution and delivery by
                  Optimal of this Agreement, and the performance by it of its


                                      -34-
<PAGE>

                  obligations hereunder and the completion of the Transaction,
                  will not:

                  (A)   result (with or without notice or the passage of time)
                        in a violation or breach of, require any consent to be
                        obtained under or give rise to any termination, purchase
                        or sale rights or payment obligation under any provision
                        of:

                        A.    Optimal's or any of its Subsidiaries' certificate
                              of incorporation, articles, by-laws or other
                              charter documents;

                        B.    any Laws (subject to obtaining the Regulatory
                              Approvals), except to the extent that the
                              violation or breach of, or failure to obtain any
                              consent would not, individually or in the
                              aggregate, reasonably be expected to prevent or
                              delay the Transaction or have a Material Adverse
                              Effect on Optimal; or

                        C.    any Contract, license, permit or government grant
                              to which Optimal or any of its Subsidiaries is
                              party or by which it is bound or is subject or is
                              the beneficiary, except as would not, individually
                              or in the aggregate, reasonably be expected to
                              prevent or delay the Transaction or have a
                              Material Adverse Effect on Optimal;

                  (B)   give rise to any right of termination or acceleration of
                        indebtedness of Optimal or any of its Subsidiaries, or
                        cause any such indebtedness to come due before its
                        stated maturity or cause any available credit of Optimal
                        or any of its Subsidiaries to cease to be available,
                        except as would not, individually or in the aggregate,
                        reasonably be expected to prevent or delay the
                        Transaction or have a Material Adverse Effect on
                        Optimal;

                  (C)   result in the imposition of any encumbrance, charge or
                        lien upon any of Optimal's assets or the assets of any
                        of its Subsidiaries except as would not, individually or
                        in the aggregate, reasonably be expected to prevent or
                        delay the Transaction or have a Material Adverse Effect
                        on Optimal; or

                  (D)   restrict, hinder, impair or limit the ability of Optimal
                        or any of its Subsidiaries to carry on business as and
                        where it is now being carried on, except as would not,
                        individually or in the aggregate, reasonably be expected
                        to prevent or delay


                                      -35-
<PAGE>

                        the Transaction or have a Material Adverse Effect on
                        Optimal.

            (v)   No consent, approval, order or authorization of, or
                  declaration or filing with, any Governmental Authority is
                  required to be obtained by Optimal and its Subsidiaries in
                  connection with the execution and delivery of this Agreement
                  or the consummation by Optimal of the Transaction other than
                  (A) the Regulatory Approvals relating to Optimal; (B) filings
                  under the Securities Act (Ontario), stock exchange rules or
                  similar laws contemplated by this Agreement or to provide
                  notice of the Transaction; (C) any filings required in
                  connection with the issue of the Optimal Shares; (D) any
                  orders or decisions obtained by Optimal from Canadian
                  securities regulatory authorities prior to Closing; and (E)
                  any other consents, approvals, orders, authorizations,
                  declarations or filings of or with a Governmental Authority
                  which are set out in the Optimal Disclosure Letter, or, with
                  respect to (D) and (E) above, which, if not obtained, would
                  not, individually or in the aggregate, reasonably be expected
                  to prevent or delay the Transaction or have a Material Adverse
                  Effect on Optimal.

      (d)   Reports. Optimal has filed with the OSC by posting on the SEDAR
            system and with the SEC by posting on the EDGAR system true and
            complete copies of all forms, reports, schedules, statements and
            other documents required in accordance with applicable Laws to be
            filed by it in the last three years. Such documents, at the time
            filed, (i) did not contain any misrepresentation of a material fact
            or omit to state a material fact required to be stated therein or
            necessary to make the statements therein, in the light of the
            circumstances under which they were made, not misleading; and (ii)
            complied in all material respects with the requirements of
            applicable securities Laws. Optimal has not filed any confidential
            material change report with any securities authority or regulator or
            any stock exchange or other self-regulatory authority which at the
            date hereof remains confidential.

      (e)   Financial Statements. The Optimal Financial Statements have been
            prepared in accordance with Canadian generally accepted accounting
            principles and applicable Laws. The Optimal Financial Statements
            present fairly, in all material respects, the consolidated financial
            position and results of operations of Optimal as of the respective
            dates thereof and for the respective periods covered thereby applied
            on a basis consistent with the immediately prior period and
            throughout the periods indicated (except as may be indicated
            expressly in the notes thereto) and in the case of unaudited
            statements, to normal, recurring year-end adjustments and the
            absence of notes. The Optimal Financial Statements reflect
            appropriate and adequate reserves in respect of contingent
            liabilities, if any, of


                                      -36-
<PAGE>

            Optimal and its Subsidiaries on a consolidated basis as of the date
            of the balance sheets contained in such statements.

      (f)   Contingent Liabilities. Except as set forth in the Optimal
            Disclosure Letter, or as Publicly Disclosed by Optimal, or for
            liabilities and obligations incurred in the ordinary course of
            business consistent with past practice since the date of the Optimal
            Balance Sheet, neither Optimal nor any of its Subsidiaries has any
            liabilities or obligations of any nature (whether accrued, absolute,
            contingent or otherwise) except for those that could not, in the
            aggregate, reasonably be expected to have a Material Adverse Effect
            on Optimal.

      (g)   Absence of Certain Changes or Events. Except as Publicly Disclosed
            by Optimal or as set out in Optimal Disclosure Letter, since
            December 31, 2003 Optimal and each of its Subsidiaries has conducted
            its business only in the ordinary and regular course of business
            consistent with past practice.

      (h)   Books and Records. Except as set out in the Optimal Disclosure
            Letter, the financial books, records and accounts of Optimal and its
            Subsidiaries, in all material respects, (i) have been maintained in
            accordance with accounting principles generally accepted in the
            country of domicile of each such entity on a basis consistent with
            prior periods, (ii) are stated in reasonable detail and accurately
            and fairly reflect the material transactions and dispositions of the
            assets of Optimal and its Subsidiaries and (iii) accurately and
            fairly reflect the basis for the Optimal Financial Statements.
            Optimal has devised and maintains a system of internal accounting
            controls sufficient to provide reasonable assurances that (i)
            transactions are executed in accordance with management's general or
            specific authorization; and (ii) transactions are recorded as
            necessary (A) to permit preparation of Optimal Financial Statements
            in conformity with Canadian generally accepted accounting
            principles, or any other criteria applicable to such statements and
            (B) to maintain accountability for assets. Except as set out in the
            Optimal Disclosure Letter, Optimal's and its Subsidiaries' corporate
            minute books contain minutes of all meetings and resolutions of the
            directors and Optimal Shareholders held, and full access thereto has
            been provided to Terra with the exception of minutes relating to the
            Transaction.

      (i)   Optimal Shares. The Optimal Shares to be issued upon the completion
            of the Transaction and upon the due exercise of the New Terra
            Options and the Terra Warrants in accordance with their terms,
            including the payment of the exercise price, will be duly and
            validly issued by Optimal on their respective dates of issue as
            fully paid and non-assessable securities and, subject to currently
            existing hold periods and compliance with section 4(4) of the 1933
            Act, the Optimal Shares to be issued upon the completion of


                                      -37-
<PAGE>

            the Transaction and upon the due exercise of the New Terra Options
            will be freely tradable in the United States.

      (j)   No Default. Neither Optimal nor any of its Subsidiaries is in
            default under, and there exists no event, condition or occurrence
            which, after notice or lapse of time or both, would constitute such
            a default under, any contract, agreement, license or franchise to
            which it is a party which would reasonably be expected to have a
            Material Adverse Effect on Optimal.

      (k)   Customers and Suppliers. Since December 31, 2002, there has been no
            termination or cancellation of, and no material adverse modification
            or change in, the business relationship with any customer or group
            of customers which individually or in the aggregate provided more
            than 5% of the consolidated gross revenues of Optimal and its
            Subsidiaries for the twelve months ended December 31, 2003.

      (l)   Litigation. Except as set out in the Optimal Disclosure Letter or
            Publicly Disclosed by Optimal: (i) there is no claim, action,
            proceeding or investigation that has been commenced or, to the
            knowledge of Optimal, threatened against Optimal or any of its
            Subsidiaries before any Governmental Authority that would reasonably
            be expected to have a Material Adverse Effect on Optimal; (ii)
            neither Optimal nor any of its Subsidiaries, nor any of their
            respective assets and properties, is subject to any outstanding
            judgment, order, writ, injunction or decree that has had or is
            reasonably likely to have a Material Adverse Effect on Optimal or
            prevent or delay consummation of the Transaction; and (iii) neither
            Optimal nor any of its Subsidiaries is subject to any material
            warranty, negligence, performance or other claims or disputes or
            potential claims or disputes in respect of products or services
            currently being delivered or previously delivered that could
            reasonably be expected to have a Material Adverse Effect on Optimal,
            and to the knowledge of Optimal there are no events or circumstances
            which could reasonably be expected to give rise to any such claims
            or disputes or potential claims or disputes.

      (m)   Restrictions on Business Activities. Except as set out in the
            Optimal Disclosure Letter, there is no agreement, judgment,
            injunction, order or decree binding upon Optimal or any of its
            Subsidiaries that has or could reasonably be expected to have the
            effect of prohibiting, restricting or materially impairing any
            material business practice of Optimal or any of its Subsidiaries,
            any acquisition of property by Optimal or any of its Subsidiaries or
            the conduct of business by Optimal or any of its Subsidiaries as
            currently conducted (including following the Transaction).

      (n)   Intellectual Property.


                                      -38-
<PAGE>

            (i)   The Optimal Disclosure Letter contains a complete and accurate
                  list of all Optimal Registered Intellectual Property and
                  specifies, where applicable, the jurisdictions in which each
                  such item of Optimal Registered Intellectual Property has been
                  issued or registered and lists any proceedings or actions
                  before any court or tribunal (including the United States
                  Patent and Trademark Office or equivalent authority anywhere
                  in the world) related to any Optimal Registered Intellectual
                  Property.

            (ii)  No Optimal Intellectual Property is subject to any proceeding
                  or outstanding decree, order, judgment, contract, license,
                  agreement, or stipulation restricting in any manner the use,
                  transfer, or licensing thereof by Optimal or any of its
                  Subsidiaries, or which may affect the validity, use or
                  enforceability of such Optimal Intellectual Property.

            (iii) Optimal owns and has good and exclusive title to, each
                  material item of Optimal Intellectual Property owned by it
                  free and clear of any lien or encumbrance (excluding
                  non-exclusive licenses and related restrictions granted in the
                  ordinary course). All Intellectual Property necessary for or
                  used in the business of Optimal and its Subsidiaries which is
                  not Optimal Intellectual Property is used by Optimal and its
                  Subsidiaries with the consent of or license from the rightful
                  owner thereof.

            (iv)  Except as set out in the Optimal Disclosure Letter, neither
                  Optimal nor any of its Subsidiaries has transferred ownership
                  of, or granted any license with respect to, any Intellectual
                  Property that is material Optimal Intellectual Property, to
                  any third party. All Optimal Intellectual Property is in full
                  force and effect and has not been used or enforced or failed
                  to have been used or enforced in a manner that would result in
                  abandonment, cancellation or unenforceability of any Optimal
                  Intellectual Property.

            (v)   The Optimal Disclosure Letter lists all material contracts,
                  licenses and agreements to which Optimal or any of its
                  Subsidiaries is a party: (A) with respect to Optimal
                  Intellectual Property licensed or transferred to any third
                  party (other than end-user licenses in the ordinary course);
                  or (B) pursuant to which a third party has licensed or
                  transferred any material Intellectual Property to Optimal.

            (vi)  All material contracts, licenses and agreements relating to
                  either (A) Optimal Intellectual Property or (B) Intellectual
                  Property of a third party licensed to Optimal or any of its
                  Subsidiaries, are in full force and effect. The consummation
                  of the transactions contemplated by this Agreement will
                  neither violate nor result in


                                      -39-
<PAGE>

                  the breach, modification, cancellation, termination or
                  suspension of such contracts, licenses and agreements. Each of
                  Optimal and its Subsidiaries is in material compliance with,
                  and has not materially breached any term of, such contracts,
                  licenses and agreements and, to the knowledge of Optimal, all
                  other parties to such contracts, licenses and agreements are
                  in compliance with, and not have materially breached any term
                  of, such contracts, licenses and agreements. Following the
                  Effective Date, Optimal will be permitted to exercise all of
                  its rights under such contracts, licenses and agreements to
                  the same extent it and its Subsidiaries would have been able
                  to had the transactions contemplated by this Agreement not
                  occurred and without the payment of any additional amounts or
                  consideration other than ongoing fees, royalties or payments
                  which it would otherwise be required to pay. Neither this
                  Agreement nor the transactions contemplated by this Agreement,
                  will result in (A) Optimal granting to any third party any
                  right to or with respect to any material Intellectual Property
                  right owned by, or licensed to it, (B) Optimal being bound by,
                  or subject to, any non-compete or other material restriction
                  on the operation or scope of its business, or (C) Optimal
                  being obligated to pay any royalties or other material amounts
                  to any third party in excess of those payable by Optimal,
                  prior to the Effective Date.

            (vii) The operation of the business of Optimal and its Subsidiaries
                  as such business currently is conducted, including (A)
                  Optimal's and its Subsidiaries' design, development,
                  manufacture, distribution, reproduction, marketing or sale of
                  the products or services of Optimal and its Subsidiaries and
                  (B) Optimal's use of any product, device or process, has not,
                  does not and, to its knowledge, will not infringe or
                  misappropriate the Intellectual Property of any third party or
                  constitute unfair competition or trade practises under the
                  laws of any jurisdiction.

           (viii) Except as set out in the Optimal Disclosure Letter or as
                  Publicly Disclosed by Optimal, neither Optimal nor any of its
                  Subsidiaries has received notice from any third party that the
                  operation of the business of Optimal or any of its
                  Subsidiaries or any act, product or service of Optimal or any
                  of its Subsidiaries, infringes or misappropriates the
                  Intellectual Property of any third party or constitutes unfair
                  competition or trade practises under the laws of any
                  jurisdiction.

            (ix)  To the knowledge of Optimal, no Person has or is infringing or
                  misappropriating any Optimal Intellectual Property. Optimal
                  has not commenced legal proceedings relating to an
                  infringement by any Person of Optimal Intellectual Property.


                                      -40-
<PAGE>

            (x)   Optimal and each of its Subsidiaries has taken reasonable
                  steps to protect Optimal's and its Subsidiaries' rights in
                  Optimal's confidential information and trade secrets that it
                  wishes to protect or any trade secrets or confidential
                  information of third parties provided to Optimal or any of its
                  Subsidiaries, and, without limiting the foregoing, each of
                  Optimal and its Subsidiaries has enforced and currently
                  enforces a policy requiring each employee and contractor to
                  execute a proprietary information/confidentiality agreement
                  and all current and former employees and contractors of
                  Optimal and any of its Subsidiaries have executed such an
                  agreement, except where the failure to do so is not reasonably
                  expected to be material to Optimal.

      (o)   Pension and Employee Benefits.

            Except as set out in the Optimal Disclosure Letter or as Publicly
            Disclosed by Optimal:

            (i)   The Optimal Benefit Plans comply in all material respects with
                  all applicable Laws and such plans have been administered in
                  compliance with applicable Laws and their terms;

            (ii)  All of the Optimal Benefit Plans that are pension plans are
                  either (A) fully insured or (B) fully funded in accordance
                  with applicable Laws on a going concern solvency basis and
                  winding-up solvency basis. Neither Optimal nor any of its
                  Subsidiaries has received, or applied for, any payment of
                  surplus out of any Optimal Benefit Plan or any payment in
                  respect of the demutualization of an insurer. Neither Optimal
                  nor its Subsidiaries has taken any contribution or premium
                  holidays under any Optimal Benefit Plan except as permitted by
                  applicable Laws and the terms of the Optimal Benefit Plan;

            (iii) None of the Optimal Benefit Plans, other than pension plans
                  which only provide monetary retirement payments in accordance
                  with the terms of such plans, provides benefits beyond
                  retirement or other termination of service to employees or
                  former employees or to the beneficiaries or dependants of such
                  employees, or such benefits have been properly accrued on the
                  Optimal Financial Statements in accordance with generally
                  accepted accounting principles;

            (iv)  No event has occurred and no condition or circumstance exists
                  that has resulted in or could reasonably be expected to result
                  in any Optimal Benefit Plan being ordered, or required to be,
                  terminated or wound up in whole or in part, having its
                  registration under applicable Laws refused or revoked, being
                  placed under the


                                      -41-
<PAGE>

                  administration of any trustee or receiver or regulatory
                  authority or being required to pay any material Taxes,
                  penalties, payments or levies under applicable Laws;

            (v)   There are no outstanding stock appreciation rights, phantom
                  equity, profit saving plan or similar rights, agreements,
                  arrangements or commitments payable to directors, officers or
                  employees based upon the revenue, value, income or any other
                  attribute of Optimal or any of its Subsidiaries; and

            (vi)  Notwithstanding anything in this Agreement to the contrary,
                  the term Optimal Benefit Plans does not include any Optimal
                  Benefit Plan that is subject to the provisions of Title I of
                  the U.S. Employee Retirement Income Security Act of 1974, as
                  amended. Each employee benefit plan that would be an Optimal
                  Benefit Plan except for the fact that it is subject to the
                  provisions of Title I of the U.S. Employee Retirement Income
                  Security Act of 1974, as amended, complies in all material
                  aspects and has been administered in compliance in all
                  material aspects with Laws and their terms and any failure to
                  so comply would not have a Material Adverse Effect on Optimal.

      (p)   Environmental. Except as set out in the Optimal Disclosure Letter or
            as Publicly Disclosed by Optimal and except for any matters that,
            individually or in the aggregate, would not reasonably be expected
            to have a Material Adverse Effect on Optimal, to the knowledge of
            Optimal:

            (i)   all operations of Optimal and its Subsidiaries have been
                  conducted, and are now, in compliance with all Environmental
                  Laws; and

            (ii)  neither Optimal nor any of its Subsidiaries is subject to:

                  (A)   any Environmental Law or terms of any environmental
                        authorization, period or licence which requires or may
                        require any material work, repairs, construction, change
                        in business practices or operations, or expenditures; or

                  (B)   any written demand, notice or order with respect to a
                        breach of or liability under any Environmental Laws
                        applicable to Optimal or any of its Subsidiaries.

      (q)   Compliance with Laws. Except as set out in the Optimal Disclosure
            Letter or as Publicly Disclosed by Optimal, Optimal and its
            Subsidiaries have complied in all material respects with and are not
            in violation of any applicable Laws, other than non-compliance or
            violations which would not, individually or in the aggregate,
            reasonably be expected to have a Material Adverse Effect on Optimal.
            Without limiting the generality of the foregoing, all securities of
            Optimal (including, all options, warrants, rights


                                      -42-
<PAGE>

            or other convertible or exchangeable securities) have been issued in
            compliance with all applicable securities Laws and all securities to
            be issued upon exercise of any such options, warrants, rights and
            other convertible or exchangeable securities will be issued in
            compliance with all applicable securities Laws.

      (r)   Tax Matters. Except as set out in the Optimal Disclosure Letter:

            (i)   Optimal and each of its Subsidiaries have filed, or caused to
                  be filed, all Tax Returns required to be filed by them in the
                  form and within the time prescribed under applicable Laws for
                  so doing (all of which Tax Returns were true and complete).
                  Terra and each of its Subsidiaries have duly and timely paid,
                  collected, withheld and remitted all Taxes (including all
                  instalments on account of Taxes) each of them is required to
                  pay, collect, withhold or remit (respectively) and the Optimal
                  Financial Statements contain an adequate provision in
                  accordance with Canadian generally accepted accounting
                  principles for all material amounts of Taxes payable in
                  respect of each period covered by such Optimal Financial
                  Statements and all prior periods to the extent such Taxes have
                  not been paid, whether or not due and whether or not shown as
                  being due on any Tax Returns. On a consolidated basis, Optimal
                  has made adequate provision in accordance with Canadian
                  generally accepted accounting principles in its books and
                  records for any material amounts of Taxes accruing in respect
                  of any accounting period which has ended subsequent to the
                  period covered by the Optimal Financial Statements.

            (ii)  All Tax Returns of Optimal and its Subsidiaries have been
                  assessed and all deficiencies proposed with respect to Optimal
                  and its Subsidiaries as a result of such assessments or
                  reassessments of the Tax Returns have been paid or settled.
                  There are no proceedings, investigations, audits or claims now
                  pending or, to the knowledge of Optimal, threatened against
                  Optimal or any of its Subsidiaries in respect of any material
                  amount of Taxes and there are no matters under discussion,
                  audit or appeal with any Governmental Authority relating to a
                  material amount of Taxes. No written claim (or to the
                  knowledge of Optimal, other claims) has ever been made by a
                  Governmental Authority in a jurisdiction where neither Optimal
                  nor any of its Subsidiaries file Tax Returns that Optimal or
                  any Subsidiary is or may be subject to taxation in that
                  jurisdiction. No Tax liens have been filed for material
                  amounts of Taxes other than for Taxes not yet due or payable.
                  Neither Optimal nor any of its Subsidiaries has acquired
                  property from another person for consideration, the value of
                  which is less than the fair market value of the property
                  acquired, in circumstances which could subject Optimal or a
                  Subsidiary, as applicable, to liability for any Taxes of


                                      -43-
<PAGE>

                  such other person who was, at the time the property was
                  acquired, a member of the same combined, affiliated, related
                  or consolidated group, or under common control with Optimal or
                  any such Subsidiary (including pursuant to section 160 of the
                  Tax Act). Since December 31, 2000, none of Optimal nor any of
                  its Subsidiaries has requested, offered to enter into or
                  entered into any agreement or other arrangement, or executed
                  any waiver, providing for any extension of time within which
                  (i) to file any Tax Return covering any Taxes for which
                  Optimal or any of its Subsidiaries is or may be liable; (ii)
                  to file any elections, designations or similar filings
                  relating to Taxes for which Optimal or any of its Subsidiaries
                  is or may be liable; or (iii) Optimal or any of its
                  Subsidiaries is required to pay or remit any Taxes or amounts
                  on account of Taxes. None of Optimal nor any of its
                  Subsidiaries has requested, offered to enter into or entered
                  into any agreement or other arrangement, or executed any
                  waiver, providing for any extension of time within which any
                  Governmental Authority may assess or collect Taxes for which
                  Optimal or any of its Subsidiaries is or may be liable.
                  Neither Optimal nor any of its Subsidiaries is a party to any
                  tax sharing or other similar agreement or arrangement of any
                  nature with any other Person (other than Optimal or any of its
                  Subsidiaries) pursuant to which Optimal or any of its
                  Subsidiaries has or could have any material liabilities in
                  respect of Taxes, other than any liability arising under an
                  agreement providing for the sale or other disposition of
                  property by Optimal or any of its Subsidiaries. Neither
                  Optimal nor any of its Subsidiaries has received a material
                  refund of any Taxes to which it was not entitled; and

            (iii) For purposes of this Section 3.2(r), the term "material amount
                  of Taxes" shall mean an amount of Taxes that is material to
                  Optimal and its Subsidiaries taken as a whole.

      (s)   Licences etc. Optimal and each of its Subsidiaries owns, possesses,
            or has obtained and is in compliance with all licences, permits,
            certificates, orders, grants and other authorizations of or from any
            Governmental Authority necessary to conduct its business as now
            conducted except where failure would not, individually or in the
            aggregate, reasonably be expected to have a Material Adverse Effect
            on Optimal.

      (t)   Property. Neither of Optimal nor any of its Subsidiaries owns any
            immovable (real) property. Neither Optimal nor any of its
            Subsidiaries is in default under any lease or sublease relating to
            immovable (real) property which would give the other party the right
            to terminate the lease or sublease as the case may be.


                                      -44-
<PAGE>

      (u)   Non-Arm's Length Transactions. Except as set out in the Optimal
            Disclosure Letter or as Publicly Disclosed by Optimal, there are no
            material Contracts or other transactions between Optimal or any of
            its Subsidiaries, on the one hand, and any (i) officer or director
            of Optimal or any of its Subsidiaries, (ii) any holder of record or
            beneficial owner of 5% or more of the voting securities of Optimal,
            or (iii) any Affiliate or associate of any such officer, director or
            beneficial owner, on the other hand.

      (v)   Fees. There are no agreements that could give rise to any claim for
            an advisory fee, success fee, brokerage commission, finder's fee or
            other like payment against Optimal or any of its Subsidiaries in
            connection with the Transaction.

      (w)   Cumulative Breach. The breaches, if any, of the representations made
            by Optimal in this Agreement that would occur if all references in
            such representations to phrases concerning materiality, were
            deleted, are not breaches that in the aggregate represent
            circumstances which (i) have or would reasonably be expected to have
            a Material Adverse Effect on Optimal, or (ii) constitute, or would
            reasonably be expected to constitute, a Material Adverse Change in
            respect of Optimal.

3.3   Survival

      For greater certainty, the representations and warranties of Terra and
Optimal contained herein shall survive the execution and delivery of this
Agreement but shall terminate on the earlier of the termination of this
Agreement in accordance with its terms and the day after the Effective Date. Any
investigation by a Party and its advisors shall not mitigate, diminish or affect
the representations and warranties of the other Party.

                                    ARTICLE 4
                                    COVENANTS

4.1   Retention of Goodwill

      During the Pre-Effective Date Period, Terra will, subject to the fact that
a transaction involving its business is contemplated hereby, continue to carry
on the business of Terra and its Subsidiaries in a manner consistent with prior
practice, working to preserve the attendant goodwill of such entities and to
contribute to retention of that goodwill to and after the Effective Date, but
subject to the following provisions of this Article 4. The provisions of Section
4.2(a) are intended to be in furtherance of this general commitment.

4.2   Covenants of Terra

      (a)   Terra covenants and agrees that, during the Pre-Effective Date
            Period, except (i) with the consent of Optimal to any deviation
            therefrom; (ii) as set out in the Disclosure Letter; (iii) as
            Publicly Disclosed by Terra; (iv)


                                      -45-
<PAGE>

            with respect to any matter expressly contemplated by this Agreement
            or Ancillary Documents, including the transactions involving the
            business of Terra and Optimal contemplated by such documents, or (v)
            as required by Law; Terra will, and will cause each of its
            Subsidiaries to:

            (i)   continue to carry on its business in the ordinary course
                  consistent with past practice in all material respects, and to
                  use commercially reasonable efforts to preserve intact its
                  present business organization and its relationships with those
                  having material business dealings with it, to the end that its
                  goodwill and business shall be maintained; provided, however,
                  that no action by Terra or its Subsidiaries with respect to
                  matters specifically addressed by any other provision of this
                  Section 4.2(a) shall be deemed a breach of this Section 4.2(a)
                  unless such action would constitute a breach of one or more of
                  such other provisions;

            (ii)  not split, consolidate or reclassify any of the outstanding
                  shares of Terra nor declare, set aside or pay any dividends on
                  or make any other distributions on or in respect of the
                  outstanding shares of Terra;

            (iii) not amend the articles or by-laws of Terra or amend the
                  articles or by-laws of any of its Subsidiaries that is not
                  wholly owned in a manner that would affect its ownership or
                  control by Terra;

            (iv)  not sell, pledge, encumber, allot, reserve, set aside or
                  issue, or purchase or redeem, any shares in its capital or the
                  capital of any of its Subsidiaries or any class of securities
                  convertible or exchangeable into, or rights, warrants or
                  options to acquire, any such shares or other securities having
                  a right to vote or convertible or exchangeable into such
                  shares or securities, except for: (A) transactions between two
                  or more wholly owned Terra Subsidiaries or between a
                  wholly-owned Subsidiary of Terra and Terra; (B) the issuance
                  of Terra Shares pursuant to Terra Options and Terra Warrants
                  granted prior to the date of this Agreement; and (C) the
                  issuance of Terra Options pursuant to Section 2.8(c);

            (v)   not amend, vary or modify the Terra Stock Option Plan, Terra
                  Options or Terra Benefit Plans involving Terra Shares or
                  phantom equity, including any action to vest unvested Terra
                  Options or accelerate the release or expiry date of any hold
                  period relating to the Terra Shares;

            (vi)  not reorganize, amalgamate or merge Terra or any of its
                  Subsidiaries with any other Person, nor acquire or agree to
                  acquire by amalgamating, merging or consolidating with,
                  purchasing a substantial equity interest or substantial
                  portion of the business of,


                                      -46-
<PAGE>

                  any business or Person, which acquisition would be material to
                  Terra's business or financial condition on a consolidated
                  basis;

            (vii) not sell, lease, encumber or otherwise dispose of any material
                  assets except (A) transactions between two or more wholly
                  owned Terra Subsidiaries or between a wholly-owned Subsidiary
                  of Terra and Terra; or (B) with respect to the sale of
                  inventory of Terra or any Subsidiary in the ordinary course of
                  business consistent with past practice;

           (viii) not:

                  (A)   in the case of directors and officers of Terra, enter
                        into or modify any employment, retention, severance, or
                        similar agreements, policies or arrangements with, or
                        grant any bonuses, salary increases, pension or
                        supplemental pension benefits, profit sharing,
                        retirement allowances, deferred compensation, incentive
                        compensation, retention, severance or termination pay to
                        or any other form of compensation to, or increase the
                        benefits payable to, or make any loan to, any officers
                        or directors of Terra or any of its Subsidiaries other
                        than as contemplated by this Agreement or required under
                        the terms of a Terra Benefit Plan, existing bonus plan
                        or written employment agreement in effect prior to the
                        date of this Agreement (or permitted to be entered under
                        this Agreement); or

                  (B)   in the case of employees who are not officers or
                        directors of Terra or any of its Subsidiaries, take any
                        action with respect to the entering into or modification
                        of any employment, retention, severance, collective
                        bargaining or similar agreements, policies or
                        arrangements or grant any bonuses, salary increases,
                        pension or supplemental pension benefits, profit
                        sharing, retirement allowances, deferred compensation,
                        incentive compensation, retention, severance or
                        termination pay or any other form of compensation that
                        are individually or in the aggregate material to Terra
                        and its Subsidiaries on a consolidated basis or increase
                        the benefits payable to, or make any loans to employees
                        that are individually or in the aggregate material to
                        Terra and its Subsidiaries on a consolidated basis,
                        other than as required by Law, or as contemplated by
                        this Agreement or as required under the terms of a Terra
                        Benefit Plan, existing bonus plan or written employment
                        agreement in effect prior to the date of this Agreement
                        (or permitted to be entered under this Agreement) or for
                        annual increases in the ordinary course of business
                        consistent with


                                      -47-
<PAGE>

                        past practice or in connection with promotions in the
                        ordinary course of business consistent with past
                        practice;

            (ix)  not guarantee the payment of material indebtedness of another
                  Person or enter into any "keep well" or other agreement having
                  the economic effect of the foregoing (other than in respect of
                  a wholly owned Affiliate or pursuant to contractual
                  obligations in effect prior to the date of this Agreement);

            (x)   not incur indebtedness for money borrowed or issue or sell any
                  debt securities or warrants or other rights to acquire debt
                  securities other than (A) in connection with the renewal or
                  replacement (on substantially equivalent terms) of existing
                  credit facilities; or (B) for short term indebtedness incurred
                  in the ordinary course of business consistent with past
                  practice;

            (xi)  not, except in the ordinary course of business consistent with
                  past practice: (A) satisfy or settle any claims or liabilities
                  substantially prior to the same being due, except such as have
                  been reserved against in the Financial Statements or which
                  are, individually or in the aggregate, not material to Terra
                  on a consolidated basis; (B) grant any waiver, exercise any
                  option or relinquish any contractual rights which are,
                  individually or in the aggregate, material to Terra on a
                  consolidated basis; or (C) enter into any interest rate,
                  currency equity or commodity swaps, hedges or other similar
                  financial instruments;

            (xii) not make any changes to existing accounting policies relating
                  to Terra or any of its Subsidiaries, except as required by Law
                  or a Government Authority or required by applicable generally
                  accepted accounting principles;

           (xiii) use its reasonable commercial efforts (or cause each of its
                  Subsidiaries to use reasonable commercial efforts) to cause
                  its current insurance (or re-insurance) policies not to be
                  cancelled or terminated or any of the coverage thereunder to
                  lapse, unless simultaneously with such termination,
                  cancellation or lapse, replacement policies underwritten by
                  insurance and re-insurance companies of nationally recognized
                  standing providing coverage equal to or greater than the
                  coverage under the cancelled, terminated or lapsed policies
                  for substantially similar premiums are in full force and
                  effect;

            (xiv) not make any loan, advances or capital contributions to, or
                  investments in, any other Person, except for:


                                      -48-
<PAGE>

                        (A)   loans or investments by Terra or a Subsidiary of
                              Terra to or in Terra or any Subsidiary of Terra
                              or, in the ordinary course of business consistent
                              with past practice, any other Person in which
                              Terra or any Subsidiary has an existing equity
                              interest; or

                        (B)   in the ordinary course of business consistent with
                              past practice which are not, individually or in
                              the aggregate, material to Terra on a consolidated
                              basis (provided that none of such transactions
                              referred to in this clause presents a material
                              risk of making it more difficult to obtain, under
                              applicable Laws, any approval or authorization
                              required in connection with the transactions
                              contemplated by this Agreement);

            (xv)  not incur or commit to any capital expenditures except in the
                  ordinary course of business provided that such capital
                  expenditures are reflect in the financial projections provided
                  to Optimal;

            (xvi) not make any changes to existing accounting practices relating
                  to Terra or any of its Subsidiaries, except as required by Law
                  or a Government Authority or required by applicable generally
                  accepted accounting principles;

            (xvii) not make or rescind any material express or deemed election
                  relating to Taxes;

            (xviii) not make a request for a Tax ruling or enter into any
                  material agreement with any Governmental Authority with
                  respect to Taxes;

            (xix) not settle or compromise any material assessment,
                  reassessment, litigation, arbitration, investigation, audit or
                  dispute relating to Taxes;

            (xx)  not change in any material respect any of its methods of
                  reporting income, deductions or accounting for Tax purposes
                  from those employed in the preparation of its most recently
                  filed Tax Returns, except as may be required by applicable
                  Law;

            (xxi) promptly inform Optimal as to any material communication in
                  respect of Taxes received by it after the date hereof from any
                  Governmental Authority;

            (xxii) not authorize, agree or propose to take any actions
                  prohibited by this Section 4.2(a).


                                      -49-
<PAGE>

      (b)   During the Pre-Effective Date Period, Terra shall and shall cause
            its Subsidiaries to perform all obligations required or desirable to
            be performed by Terra or any of its Subsidiaries under this
            Agreement, co-operate with Optimal in connection therewith, and do
            all such other acts and things as may be necessary or desirable in
            order to consummate and make effective, as soon as reasonably
            practicable, the transactions contemplated in this Agreement and,
            without limiting the generality of the foregoing, Terra shall and
            where appropriate shall cause its Subsidiaries to:

            (i)   use commercially reasonable efforts to obtain the requisite
                  approvals of the Terra Shareholders to the Terra Resolution
                  including participating in joint presentations to Terra
                  Shareholders and Optimal Shareholders, except to the extent
                  that the board of directors of Terra has withdrawn, modified
                  or qualified its recommendation to shareholders in accordance
                  with the terms of this Agreement;

            (ii)  advise Optimal as requested, and on a daily basis on each of
                  the last seven Business Days prior to the Terra Meeting as to
                  the aggregate tally of the proxies and votes received in
                  respect of the Terra Meeting and all matters to be considered
                  at such meeting;

            (iii) apply for and use commercially reasonable efforts to obtain
                  all Regulatory Approvals relating to Terra or any of its
                  Subsidiaries or to the Transaction and, in doing so, to keep
                  Optimal informed as to the status of the proceedings related
                  to obtaining the Regulatory Approvals, including, but not
                  limited to, providing Optimal with copies of all related
                  applications and notifications, in draft form, in order for
                  Optimal to provide its reasonable comments and providing
                  Optimal with copies of all material correspondence;

            (iv)  use commercially reasonable efforts to effect all necessary
                  registrations, filings and submissions of information required
                  by Governmental Authorities from Terra or any of its
                  Subsidiaries relating to the Transaction;

            (v)   use commercially reasonable efforts to obtain all necessary
                  waivers, consents and approvals required to be obtained by
                  Terra or any of its Subsidiaries in connection with the
                  Transaction from other parties to any material loan
                  agreements, leases or other material contracts;

            (vi)  use commercially reasonable efforts to comply promptly with
                  all requirements which applicable Laws may impose on Terra or
                  its Subsidiaries with respect to the transactions contemplated
                  by this Agreement;


                                      -50-
<PAGE>

            (vii) use commercially reasonable efforts to defend all lawsuits and
                  other legal, regulatory or other proceedings to which it is a
                  party, challenging or affecting this Agreement or the
                  consummation of the transactions contemplated by this
                  Agreement;

           (viii) use commercially reasonable efforts to have lifted or
                  rescinded any injunction or restraining order relating to
                  Terra or other order which may adversely affect the ability of
                  the Parties to consummate the transactions contemplated by
                  this Agreement;

            (ix)  provide Optimal with a copy of any purported exercise of the
                  Dissent Rights and written communications with any holders
                  exercising or purporting to exercise Dissent Rights; and not
                  settle or compromise any claim brought by any present, former
                  or purported holder of any of its securities in connection
                  with the Transaction;

            (x)   promptly advise Optimal orally and, if then requested, in
                  writing:

                  (A)   of any event occurring subsequent to the date of this
                        Agreement that would render any representation or
                        warranty of Terra contained in this Agreement (except
                        any such representation or warranty which speaks solely
                        as of a date prior to the occurrence of such event), if
                        made on or as of the date of such event or the Effective
                        Time, untrue or inaccurate in any material respect;

                  (B)   of any Material Adverse Change in respect of Terra; and

                  (C)   of any material breach by Terra of any covenant or
                        agreement contained in this Agreement; and

            (xi)  use commercially reasonable efforts to ensure that Terra's
                  Affiliates (for the purposes of Rule 145 under the 1933 Act)
                  execute and deliver an Affiliate's Letter to Optimal on or
                  prior to the Effective Date.

4.3   Covenants of Optimal

      (a)   Optimal covenants and agrees that, during the Pre-Effective Date
            Period, except (i) with the consent of Terra to any deviation
            therefrom, which consent shall not be unreasonably withheld or
            delayed; (ii) as set out in the Optimal Disclosure Letter; (iii) as
            Publicly Disclosed by Optimal; (iv) with respect to any matter
            expressly contemplated by this Agreement or Ancillary Documents,
            including the transactions involving the business of Optimal and
            Terra contemplated by such documents; or (v) as required by Law;
            Optimal will, and will cause each of its Subsidiaries to:


                                      -51-
<PAGE>

            (i)   not split, consolidate or, except as permitted by Section 4.8,
                  reclassify any of the outstanding shares of Optimal nor
                  declare, set aside or pay any dividends on or make any other
                  distributions on or in respect of the outstanding shares of
                  Optimal;

            (ii)  except as permitted by Section 4.8, not amend the articles or
                  by-laws of Optimal or amend the articles or by laws of any of
                  its Subsidiaries that is not wholly owned in a manner that
                  would affect its ownership or control by Optimal;

            (iii) not purchase or redeem any shares in its capital or the
                  capital of any of its Subsidiaries or any class of securities
                  convertible or exchangeable into, or rights, warrants or
                  options to acquire, any such shares or other securities having
                  a right to vote or convertible or exchangeable into such
                  shares or securities, except for transactions between two or
                  more wholly owned Optimal Subsidiaries or between a wholly
                  owned Subsidiary of Optimal and Optimal;

            (iv)  except as permitted by Section 4.8, not reorganize, amalgamate
                  or merge Optimal or any of its Subsidiaries with any other
                  Person;

            (v)   not change in any material respect any of its methods of
                  reporting income, deductions or accounting for Tax purposes
                  from those employed in the preparation of its most recently
                  filed Tax Returns, except as may be required by applicable
                  Law; and

            (vi)  not authorize, agree or propose to take any actions prohibited
                  by this Section 4.3(a).

      (b)   Optimal shall and shall cause its Subsidiaries to perform all
            obligations required or desirable to be performed by Optimal or by
            any of its Subsidiaries under this Agreement, to co-operate with
            Terra in connection therewith, and to do all such other acts and
            things as may be necessary or desirable in order to consummate and
            make effective, as soon as reasonably practicable, the transactions
            contemplated by this Agreement and, without limiting the generality
            of the foregoing:

            (i)   to apply for and use commercially reasonable efforts to obtain
                  all Regulatory Approvals relating to the Transaction and, in
                  doing so, to keep Terra informed as to the status of the
                  proceedings related to obtaining the Regulatory Approvals,
                  including, but not limited to, providing Terra with copies of
                  all related applications and notifications, in draft form, in
                  order for Terra to provide its reasonable comments and
                  providing Terra with copies of all material correspondence;


                                      -52-
<PAGE>

            (ii)  to effect all necessary registrations, filings and submissions
                  of information required by Governmental Authorities from
                  Optimal or its Subsidiaries relating to the Transaction;

            (iii) to use commercially reasonable efforts to comply promptly with
                  all requirements which applicable Laws may impose on Optimal
                  or its Subsidiaries with respect to the transactions
                  contemplated by this Agreement;

            (iv)  to use commercially reasonable efforts to defend all lawsuits
                  or other legal, regulatory or other proceedings, to which it
                  is a party, challenging or affecting this Agreement or the
                  consummation of the transactions contemplated by this
                  Agreement;

            (v)   to use commercially reasonable efforts to have lifted or
                  rescinded any injunction or restraining order or other order
                  relating to Optimal which may adversely affect the ability of
                  the Parties to consummate the transactions contemplated by
                  this Agreement; and

            (vi)  to promptly advise Terra orally and, if then requested, in
                  writing:

                  (A)   of any event occurring subsequent to the date of this
                        Agreement that would render any representation or
                        warranty of Optimal contained in this Agreement (except
                        any such representation or warranty which speaks solely
                        as of a date prior to the occurrence of such event), if
                        made on or as of the date of such event or the Effective
                        Time, untrue or inaccurate in any material respect;

                  (B)   of any Material Adverse Change in respect of Optimal;
                        and

                  (C)   of any material breach by Optimal of any covenant or
                        agreement contained in this Agreement.

4.4   Terra Covenants Regarding Non-Solicitation

      (a)   Terra shall, and shall cause the officers, directors, employees,
            representatives and agents of Terra and its Subsidiaries to, cease
            immediately all current discussions and negotiations regarding any
            proposal that constitutes, or may reasonably be expected to lead to,
            an Acquisition Proposal, and request and enforce the return or
            destruction of all confidential information provided in connection
            therewith. Terra shall not release any third party from any
            confidentiality agreement or standstill agreement. Prior to the
            Effective Time, Terra shall confirm to Optimal that third parties
            with whom it has discussed any Acquisition Proposal in the last six
            months have either returned such confidential information or have
            certified its destruction.


                                      -53-
<PAGE>

      (b)   Subject to Section 4.5, Terra shall not, directly or indirectly,
            through any officer, director, employee, representative (including
            for greater certainty any investment banker, lawyer or accountant)
            or agent of Terra or any of its Subsidiaries (i) solicit, initiate,
            knowingly encourage or otherwise facilitate (including by way of
            furnishing information or entering into any form of agreement,
            arrangement or understanding) the initiation of any inquiries or
            proposals regarding an Acquisition Proposal, (ii) participate in any
            discussions or negotiations regarding, or provide any confidential
            information with respect to, any Acquisition Proposal, (iii) approve
            or recommend, or publicly propose to approve or recommend, any
            Acquisition Proposal, or (iv) accept or enter into, or publicly
            propose to accept or enter into, any letter of intent, agreement,
            arrangement or understanding related to any Acquisition Proposal.

      (c)   Notwithstanding Section 4.4(b) and any other provision of this
            Agreement, nothing shall prevent the board of directors of Terra
            from (i) taking any action to the extent ordered or otherwise
            mandated by any court of competent jurisdiction, or (ii) from
            considering, participating in any discussions or negotiations, or
            entering into a confidentiality agreement and providing information
            pursuant to Section 4.4(e), if and only to the extent that, in any
            such case referred to in clause (ii), (A) Terra has complied with
            Section 4.4 and (B) the board of directors of Terra concludes in
            good faith in the case of clause (ii), after consultation with their
            outside legal and financial advisors, that (x) any required
            financing of such Acquisition Proposal is reasonably likely to be
            obtained; and that (y) in the case of clause (ii) that, after taking
            the steps contemplated in clause (ii), it is reasonably likely that
            the board of directors of Terra would determine that such
            Acquisition Proposal is a Superior Proposal.

      (d)   Terra shall forthwith notify Optimal of any Acquisition Proposal and
            any inquiry of which a director or an officer of Terra or Terra's
            financial advisor is made aware that could lead to an Acquisition
            Proposal, or any amendments to the foregoing, or any request for
            non-public information relating to Terra or any of its Subsidiaries
            in connection with an Acquisition Proposal or for access to the
            properties, books or records of Terra or any of its Subsidiaries by
            any Person. Such notice shall include a description of the material
            terms and conditions of any proposal, the identity of the Person
            making such proposal, inquiry or contact and provide such other
            details of the proposal, inquiry or contact as Optimal may
            reasonably request. Terra shall promptly (and in any event within 24
            hours) advise Optimal of any material modification or proposed
            modification to any such Acquisition Proposal or inquiry.

      (e)   If Terra receives a request for material non-public information from
            a Person who has made an unsolicited bona fide written Acquisition
            Proposal and Terra is permitted, subject to and as contemplated
            under Section 4.4(c), to negotiate the terms of such Acquisition
            Proposal, then,


                                      -54-
<PAGE>

            and only in such case, the board of directors of Terra may, subject
            to the execution by such Person of a confidentiality agreement
            containing employee non-solicitation provisions substantially
            similar to those contained in this Agreement and the Confidentiality
            Agreement provide such Person with access to information regarding
            Terra; provided that Terra sends a copy of any such confidentiality
            agreement to Optimal promptly upon its execution and Optimal is
            provided with a list of, and copies of, the information provided to
            such Person and is also provided upon request with access to similar
            information to which such Person was provided on a timely basis.

      (f)   Terra shall ensure that its officers, directors and employees and
            its Subsidiaries and their officers, directors and employees and any
            financial advisors or other advisors or representatives retained by
            it or its Subsidiaries are aware of the provisions of this Section
            4.4, and Terra shall be responsible for any breach of this Section
            4.4 by its and its Subsidiaries' officers, directors, employees,
            representatives or agents.

4.5   Matching Rights

      (a)   Notwithstanding Section 4.4(b), Terra may accept, approve, recommend
            or enter into any agreement, understanding or arrangement in respect
            of an unsolicited Superior Proposal if, and only if: (i) it has
            complied with this Article 4; (ii) it has provided Optimal with a
            copy of the Superior Proposal document; (iii) five Business Days
            (the "Match Period") shall have elapsed from the later of the date
            Optimal received written notice advising Optimal that Terra's board
            of directors has resolved, subject only to compliance with this
            Section 4.5, to accept, approve, recommend or enter into an
            agreement, understanding or arrangement in respect of such Superior
            Proposal and the date Optimal received a copy of such Superior
            Proposal and (iv) at the Expiry of the Match Period it remains a
            Superior Proposal under Section 4.5(b). In such circumstances,
            Terra's board of directors may also withdraw, modify or qualify its
            recommendation of the Transaction. In the event that Terra provides
            Optimal with the notice contemplated in this Section on a date that
            is less than five Business Days prior to the Terra Meeting, if
            requested by Optimal, Terra shall adjourn the Terra Meeting to a
            date that is not less than seven Business Days and not more than ten
            Business Days after the date of such notice.

      (b)   During the Match Period, Terra agrees that Optimal shall have the
            right, but not the obligation, to offer to amend the terms of this
            Agreement. The board of directors of Terra will review any offer by
            Optimal to amend the terms of this Agreement in good faith in order
            to determine, in its discretion in the exercise of its fiduciary
            duties (but without regard to any requirement for approval or
            further approval by Optimal's Shareholders, unless it has reasonable
            grounds to expect that such shareholder approval will not be
            obtained), whether Optimal's offer upon acceptance by Terra


                                      -55-
<PAGE>

            would result in such Superior Proposal ceasing to be a Superior
            Proposal. If the board of directors of Terra so determines, it will
            enter into an amended agreement with Optimal reflecting Optimal's
            amended proposal. If the board of directors of Terra continues to
            believe, in good faith, after consultation with its financial
            advisors and outside counsel, that such Superior Proposal remains a
            Superior Proposal (without regard to any requirement for approval or
            further approval by Optimal's Shareholders, unless it has reasonable
            grounds to expect that such shareholder approval will not be
            obtained) and therefore rejects Optimal's amended proposal, at the
            expiry of the Match Period in accordance with Section 4.5(a), Terra
            may approve, recommend, accept or enter into an agreement,
            understanding or arrangement with respect to the Superior Proposal;
            provided that such acceptance or agreement does not obligate Terra
            or any other Person to seek to interfere with the completion of the
            Transaction or impose on Terra or any subsidiary any "break",
            "hello" or other fees or options or rights to acquire assets or
            securities, or any other obligations that would survive the
            Effective Date, unless and until this Agreement is terminated in
            accordance with its terms and the fees referred to in Section 6.3(a)
            are paid. In addition, in such circumstances, Terra may proceed with
            such approvals, consents, filings with, of or required by
            Governmental Authorities and such other Person as Terra shall
            consider appropriate in order to consummate such Superior Proposal,
            provided that such activity does not interfere with the completion
            of the Transaction. If as a result of the application of this
            Section 4.5 there is another Acquisition Proposal that is a Superior
            Proposal to be considered at the Terra Meeting, the order of
            presentation, signage, proxy forms and other matters related thereto
            shall be acceptable to Optimal.

      (c)   Subject to the last sentence of Section 4.5(a), nothing contained in
            this Section 4.5 shall limit in any way the obligation of Terra to
            convene and hold the Terra Meeting in accordance with Section 2.2 of
            this Agreement.

      (d)   Terra acknowledges and agrees that each successive material
            amendment to any Acquisition Proposal, including any amendment to
            the consideration for Terra Shares, shall constitute a new
            Acquisition Proposal requiring the initiation of a new Match Period
            in respect of that amended Acquisition Proposal.

4.6   Access to Information

      (a)   Subject to applicable Laws, upon reasonable notice, Terra shall (and
            shall cause each of its Subsidiaries to) afford Optimal's officers,
            employees, counsel, accountants and other authorized representatives
            and advisors ("Representatives") access, during normal business
            hours from the date hereof and until the earlier of the Effective
            Date or the termination of this Agreement, to its and its
            Subsidiaries' properties, books, contracts and records as well as to
            its management personnel, and, during such period,


                                      -56-
<PAGE>

            Terra shall (and shall cause each of its Subsidiaries to) furnish
            promptly to Optimal all information concerning Terra's and its
            Subsidiaries' businesses, properties and personnel as Optimal may
            reasonably request. Subject to applicable Laws, upon reasonable
            notice, Optimal shall afford Terra's Representatives the
            opportunity, upon reasonable notice and during normal business hours
            from the date hereof and until the earlier of the Effective Date or
            termination of this Agreement, to speak to appropriate Optimal
            management personnel as Terra may reasonably request, without
            materially interfering with their other responsibilities.

4.7   Optimal Board Designees

      At the Effective Time, Optimal shall cause two mutually agreed upon
individuals to be appointed to the board of directors of Optimal (the "Optimal
Board") and shall cause such individuals to be nominated for election to the
Optimal Board at the next annual meeting of Optimal Shareholders.

4.8   Optimal Covenant Regarding Non-Solicitation

      During the Pre-Effective Date Period, Optimal shall not, directly or
indirectly, through any officer, director, employee, representative (including
for greater certainty any investment banker, lawyer or accountant) or agent of
Optimal or any of its Subsidiaries, solicit, initiate, knowingly encourage or
otherwise facilitate (including by way of furnishing information or entering
into any form of agreement, arrangement or understanding) the initiation of any
inquiries or proposals regarding a Change of Control; provided, however, that
nothing contained in this Section 4.8 or any other provision of this Agreement
shall prevent the Optimal Board from responding to an unsolicited proposal or
offer from, providing information to, or entering into any agreement with, any
other Person, if the Optimal Board determines in good faith that it is required
to do so in order to properly discharge its fiduciary duties.

4.9   Indemnification

      (a)   Optimal agrees that all rights to indemnification or exculpation
            existing in favour of the directors or officers of Terra or any
            Subsidiary as provided in its articles or by-laws as at the date of
            the Confidentiality Agreement shall survive the Transaction and
            shall continue in full force and effect for a period of not less
            than six years from the Effective Time.

      (b)   There shall be maintained in effect, for not less than six years
            from the Effective Time, coverage substantially equivalent to that
            in effect under the current policies of the directors' and officers'
            liability insurance maintained by Terra or any of its Subsidiaries,
            as the case may be, which is no less advantageous, and with no gaps
            or lapses in coverage with respect to matters occurring prior to the
            Effective Time; provided that in no event shall Optimal be required
            to expend in any one year an amount in excess of 200% and if the
            annual premiums of such insurance coverage


                                      -57-
<PAGE>

            exceed such amount, Optimal shall be obligated to obtain a
            substantially similar policy with the greatest coverage available
            (as to quantum and events) for such maximum cost. Alternatively, at
            Optimal's option, it may cause Terra to purchase "run-off"
            directors' and officers' liability insurance providing coverage
            substantially as favourable to such directors and officers as that
            in effect under such current policies to cover prior events during
            such six year period or the balance thereof.

                                    ARTICLE 5
                                   CONDITIONS

5.1   Mutual Conditions Precedent

      The respective obligations of the Parties to complete the Transaction
shall be subject to the satisfaction, on or before the Effective Time, of the
following conditions precedent, each of which may only be waived by the mutual
consent of Optimal and Terra:

      (a)   the Terra Resolution shall have been approved at the Terra Meeting
            by not less than 66 2/3% of votes cast by the Terra Shareholders who
            are represented at the Terra Meeting;

      (b)   the Articles of Amalgamation shall be in content consistent with
            this Agreement and in form satisfactory to the Parties acting
            reasonably in that context;

      (c)   the Optimal Shareholders shall have approved the Optimal Resolution
            at the Optimal Meeting by a simple majority of the votes cast at the
            Optimal Meeting;

      (d)   there shall not be in force any Law, final and non-appealable
            injunction, order or decree prohibiting, restraining or enjoining
            the consummation of the Transaction;

      (e)   the Regulatory Approvals shall have been obtained or satisfied on
            terms and conditions satisfactory to Optimal and Terra acting
            reasonably, (but in case of Terra only insofar as it would directly
            materially adversely affect Terra Shareholders);

      (f)   other than the Regulatory Approvals, all consents, waivers, permits,
            orders and approvals of any Governmental Authority, and the expiry
            of any waiting periods, in connection with, or required to permit,
            the consummation of the Transaction, the failure of which to obtain
            or the non-expiry of which would constitute a criminal offence or
            would have a Material Adverse Effect on Optimal or Terra, as the
            case may be, shall have been obtained or satisfied on terms that
            could not reasonably be expected to have a Material Adverse Effect
            on Optimal and/or Terra;


                                      -58-
<PAGE>

      (g)   the orders referred to in Section 2.6 shall have been obtained, and
            the Optimal Shares issuable pursuant to the Transaction and upon the
            exercise of the New Terra Options, the Terra Warrants, the Terra
            Broker Warrants, the AOL Warrant and the EBS Warrant shall have been
            approved for quotation on NASDAQ, subject to the filing of required
            documentation, notice of issuance and/or other usual requirements
            and compliance with all applicable securities laws; and

      (h)   this Agreement shall not have been terminated pursuant to Article 6.

5.2   Additional Conditions Precedent to the Obligations of Optimal

      (a)   The obligation of Optimal to complete the Transaction shall also be
            subject to the fulfillment of each of the following conditions
            precedent (each of which is for Optimal's exclusive benefit and may
            be waived by Optimal):

            (i)   all covenants of Terra under this Agreement to be performed on
                  or before the Effective Time shall have been duly performed by
                  Terra and Optimal shall have received a certificate of Terra
                  addressed to Optimal and dated the Effective Date, signed on
                  behalf of Terra by two senior executive officers of Terra (on
                  Terra's behalf and without personal liability), confirming the
                  same as at the Effective Date;

            (ii)  (A) the representations and warranties of Terra that are
                  qualified by references to materiality shall be true and
                  correct; (B) the representations and warranties of Terra not
                  so qualified (except Section 3.1(a), Section 3.1(b) and
                  Section 3.1(c)(i) through (iii)) shall be true and correct in
                  all material respects; and (C) the representations in Section
                  3.1(a), Section 3.1(b) and Section 3.1(c)(i) through (iii)
                  shall be true and correct, in each case as of the Effective
                  Time as if made on and as of such time (except to the extent
                  such representations and warranties speak solely as of an
                  earlier date, in which event such representations and
                  warranties shall be true and correct to such extent as of such
                  earlier date, or except as affected by transactions
                  contemplated or permitted by this Agreement), and Optimal
                  shall have received a certificate of Terra addressed to Terra
                  and dated the Effective Date, signed on behalf of Terra by two
                  senior executive officers of Terra (on Terra's behalf and
                  without personal liability), confirming the same as at the
                  Effective Date;

            (iii) the board of directors of Terra shall have adopted all
                  necessary resolutions, and all other necessary corporate
                  action shall have


                                      -59-
<PAGE>

                  been taken by Terra and its Subsidiaries to permit the
                  consummation of the Transaction;

            (iv)  during the Pre-Effective Date Period, there shall not have
                  occurred or have been disclosed to the public, in each case if
                  previously undisclosed to the public or Optimal, a Material
                  Adverse Change to Terra;

            (v)   there shall not be pending or threatened in writing any suit,
                  action or proceeding by any Person: (A) seeking to prohibit or
                  restrict the acquisition by Optimal or any of its Subsidiaries
                  of any Terra Shares, seeking to restrain or prohibit the
                  consummation of the Transaction or seeking to obtain from
                  Terra or Optimal any material damages directly or indirectly
                  in connection with the Transaction, (B) seeking to prohibit or
                  materially limit the ownership or operation by Optimal or any
                  of its Subsidiaries of Terra or any material portion of the
                  business or assets of Terra or any of its Subsidiaries or to
                  compel Optimal or any of its Subsidiaries to dispose of or
                  hold separate any portion of the business or assets of Terra
                  or any of its Subsidiaries, (C) seeking to impose limitations
                  on the ability of Optimal or any of its Subsidiaries to
                  acquire or hold, or exercise full rights of ownership of, any
                  Terra Shares, including the right to vote the Terra Shares to
                  be acquired by them on all matters properly presented to the
                  shareholders of Terra, (D) seeking to prohibit Optimal or any
                  of its Subsidiaries from effectively controlling in any
                  material respect the business or operations of Terra or any of
                  its Subsidiaries or (E) which, if successful, in the judgement
                  of Optimal is reasonably likely to have a Material Adverse
                  Effect on Terra or Optimal; and

            (vi)  the Holders of Terra Shares representing in excess of 10% of
                  the outstanding Terra Shares shall not have exercised Dissent
                  Rights in connection with the Amalgamation that have not been
                  withdrawn.

      (b)   Optimal may not rely on the failure to satisfy any of the conditions
            precedent in Section 5.1 or Section 5.2 if the condition precedent
            would have been satisfied but for a material default by Optimal in
            complying with its obligations in this Agreement.

5.3   Additional Conditions Precedent to the Obligations of Terra

      (a)   The obligation of Terra to complete the Transaction shall also be
            subject to the following conditions precedent (each of which is for
            the exclusive benefit of Terra and may be waived by Terra):

            (i)   all covenants of Optimal under this Agreement to be performed
                  on or before the Effective Time shall have been duly
                  performed, and


                                      -60-
<PAGE>

                  Terra shall have received a certificate of Optimal addressed
                  to Terra and dated the Effective Date, signed on behalf of
                  Optimal by two senior executive officers of Optimal (on
                  Optimal's behalf and without personal liability), confirming
                  the same as at the Effective Date;

            (ii)  (A) the representations and warranties of Optimal that are
                  qualified by references to materiality shall be true and
                  correct; (B) the representations and warranties of Optimal not
                  so qualified (except Section 3.2(a), Section 3.2(b) and
                  Section 3.2(c)(i) through (iii)) shall be true and correct in
                  all material respects; and (C) the representations in Section
                  3.2(a), Section 3.2(b) and Section 3.2(c)(i) through (iii)
                  shall be true and correct, in each case as of the Effective
                  Time as if made on and as of such time except to the extent
                  such representations and warranties speak solely as of an
                  earlier date, in which event such representations and
                  warranties shall be true and correct to such extent as of such
                  earlier date, or except as affected by transactions
                  contemplated or permitted by this Agreement), and Terra shall
                  have received a certificate of Optimal addressed to Terra and
                  dated the Effective Date, signed on behalf of Optimal by two
                  senior executive officers of Optimal (on Optimal's behalf and
                  without personal liability), confirming the same as at the
                  Effective Date;

            (iii) the Optimal Board shall have adopted all necessary
                  resolutions, and all other necessary corporate action shall
                  have been taken by Optimal to permit the consummation of the
                  Transaction and the issue of Optimal Shares upon the due
                  exercise of New Terra Options and the Terra Warrants in
                  accordance with their terms, including the payment of the
                  exercise price;

            (iv)  during the Pre-Effective Date Period, there shall not have
                  occurred or have been disclosed to the public, in each case if
                  previously undisclosed to the public or Terra, a Material
                  Adverse Change to Optimal; and

            (v)   there shall not be pending or threatened in writing any suit,
                  action or proceeding by any Person: (A) seeking to prohibit or
                  restrict the acquisition by Terra Shareholders of any Optimal
                  Shares, seeking to restrain or prohibit the consummation of
                  the Transaction or seeking to obtain from Optimal or Terra any
                  material damages directly or indirectly in connection with the
                  Transaction, or (B) which, if successful, in the judgement of
                  Terra is reasonably likely to have a Material Adverse Effect
                  on Optimal or Terra.

      (b)   Terra may not rely on the failure to satisfy any of the conditions
            precedents in Section 5.1 or Section 5.3 if the condition precedent
            would


                                      -61-
<PAGE>

            have been satisfied but for a material default by Terra in complying
            with its obligations in this Agreement.

5.4   Notice and Cure Provisions

      (a)   Optimal and Terra will give prompt notice to the other of the
            occurrence, or failure to occur, at any time during the
            Pre-Effective Period of any event or state of facts which occurrence
            or failure would, or would be likely to:

            (i)   cause any of the representations or warranties of it contained
                  in this Agreement to be untrue or inaccurate on the date
                  hereof or on the Effective Time such that the conditions set
                  forth in Section 5.2 or Section 5.3, as applicable, would not
                  be satisfied as of the Effective Time; or

            (ii)  result in the failure in any material respect to comply with
                  or satisfy any covenant, condition or agreement to be complied
                  with or satisfied by the other under this Agreement prior to
                  the Effective Time such that the conditions set forth in
                  Section 5.2 or Section 5.3, as applicable, would not be
                  satisfied as of the Effective Time.

      (b)   Neither Optimal nor Terra may seek to rely upon any conditions
            precedent contained in Section 5.1, Section 5.2 or Section 5.3, or
            exercise any termination right arising therefrom, unless forthwith
            and in any event prior to the filing of the Articles of Amalgamation
            for acceptance by the Director, Optimal or Terra, as the case may
            be, has delivered a written notice to the other specifying in
            reasonable detail all breaches of covenants, representations and
            warranties or other matters which Optimal or Terra, as the case may
            be, are asserting as the basis for the non-fulfillment of the
            applicable condition precedent or the exercise of the termination
            right, as the case may be. If any such notice is delivered, provided
            that Terra or Optimal, as the case may be, is proceeding diligently
            to cure such matter, if such matter is susceptible to being cured
            (for greater certainty, except by way of disclosure in the case of
            representations and warranties), the other may not terminate this
            Agreement as a result thereof until the earlier of the Outside Date
            and 60 days from delivery of such notice. If such notice has been
            delivered prior to the date of the Terra Meeting and/or the Optimal
            Meeting, such meetings shall, unless the Parties agree otherwise, be
            postponed or adjourned until the expiry of such period. If such
            notice has been delivered prior to the filing of the Articles of
            Amalgamation with the Director, such filing shall be postponed until
            the expiry of such period. For greater certainty, in the event that
            such matter is cured within the time period referred to herein
            without a Material Adverse Effect on the Party in


                                      -62-
<PAGE>

            breach, this Agreement may not be terminated as a result of the
            cured breach.

5.5   Satisfaction of Conditions

      The conditions precedent set out in Section 5.1, Section 5.2 and Section
5.3, shall be conclusively deemed to have been satisfied, waived or released
when, with the agreement of Optimal and Terra, a Certificate of Amalgamation in
respect of the Amalgamation is issued by the Director.

                                    ARTICLE 6
                            AMENDMENT AND TERMINATION

6.1   Amendment

      (a)   This Agreement may, at any time and from time to time before or
            after the holding of the Terra Meeting or the Optimal Meeting but
            not later than the Effective Date, be amended by mutual written
            agreement of the Parties, and any such amendment may, without
            further shareholder approvals, subject to applicable Laws, without
            limitation:

            (i)   change the time for performance of any of the obligations or
                  acts of the Parties;

            (ii)  waive any inaccuracies or modify any representation or
                  warranty contained in this Agreement or in any document
                  delivered pursuant to this Agreement;

            (iii) waive compliance with or modify any of the covenants contained
                  in this Agreement and waive or modify performance of any of
                  the obligations of the Parties; and/or

            (iv)  waive compliance with or modify any conditions precedent
                  contained in this Agreement provided that any such change does
                  not decrease the consideration payable to Terra Shareholders.

      (b)   During the Pre-Effective Date Period, the Parties will use
            commercially reasonable efforts to maximize present and future
            financial and tax planning opportunities for Optimal and Terra as a
            subsidiary of Optimal as and to the extent that the same shall not
            prejudice any Party or its securityholders. The Parties will ensure
            that such planning activities do not impede the progress of the
            Transaction in any material way. If, at the request of Optimal,
            Terra effects any transaction before the Effective Date for such
            purposes, Optimal will be responsible for any structuring and
            unwinding costs if the Transaction is not consummated.


                                      -63-
<PAGE>

6.2   Termination

      (a)   If any condition contained in Section 5.1 or Section 5.2 is not
            satisfied at or before the Effective Time, then Optimal may, subject
            to Section 5.4 and to Section 5.2(b), by notice to Terra terminate
            this Agreement and the obligations of the Parties hereunder (except
            as otherwise herein provided, including under Section 6.3), but
            without detracting from the rights of Optimal arising from any
            breach by Terra but for which the condition would have been
            satisfied.

      (b)   If any condition contained in Section 5.1 or Section 5.3 is not
            satisfied at or before the Effective Time, then Terra may, subject
            to Section 5.4 and to Section 5.3(b), by notice to Optimal terminate
            this Agreement and the obligations of the Parties hereunder (except
            as otherwise herein provided, including under Section 6.3), but
            without detracting from the rights of Terra arising from any breach
            by Optimal but for which the condition would have been satisfied.

      (c)   This Agreement may:

            (i)   be terminated by the mutual agreement of Terra and Optimal,
                  (and for greater certainty, without further action on the part
                  of the Terra Shareholders or the Optimal Shareholders if
                  terminated after the holding of the Terra Meeting or the
                  Optimal Meeting, as applicable);

            (ii)  be terminated by either Terra or Optimal if there shall be
                  passed any Law that makes consummation of the Amalgamation
                  illegal or otherwise prohibited;

            (iii) be terminated by Optimal, if (A) the board of directors of
                  Terra shall have failed to recommend or shall have withdrawn,
                  modified or changed in a manner adverse to Optimal its
                  approval or recommendation of this Agreement, the Transaction
                  or the Terra Resolution (unless the condition set forth in
                  Section 5.3(a)(iv) is not satisfied or Optimal shall have made
                  a misrepresentation at the date hereof or breached a covenant
                  under this Agreement in such a manner that, taking into
                  account Section 5.3(b) and Section 5.4, Terra would be
                  entitled to rely on the failure of a condition set forth in
                  Section 5.3(a) as a reason not to complete the Transaction),
                  or (B) the board of directors of Terra shall have approved or
                  recommended any Acquisition Proposal other than the
                  Transaction;

            (iv)  be terminated by Terra, if the Optimal Board shall have failed
                  to recommend or shall have withdrawn, modified or changed in a
                  manner adverse to Terra its approval or recommendation of this


                                      -64-
<PAGE>

                  Agreement, the Transaction or the Optimal Resolution (unless
                  the condition set forth in Section 5.2(a)(iv) is not satisfied
                  or Terra shall have made a misrepresentation at the date
                  hereof or breached a covenant under this Agreement in such a
                  manner that, taking into account Section 5.2(b) and Section
                  5.4, Optimal would be entitled to rely on the failure of a
                  condition set forth in Section 5.25.2(a) as a reason not to
                  complete the Transaction);

            (v)   be terminated by either Optimal or Terra, if either the Terra
                  Shareholder approval or Optimal Shareholder approval shall not
                  have been obtained by reason of the failure to obtain the
                  requisite vote set out in Section 5.1 at the Terra Meeting or
                  the Optimal Meeting, respectively;

            (vi)  be terminated by Optimal if the Terra Meeting has not occurred
                  on or before the Terra Meeting Date (unless the condition set
                  forth in Section 5.3(a)(iv) is not satisfied or Optimal shall
                  have made a misrepresentation at the date hereof or breached a
                  covenant under this Agreement in such a manner that, taking
                  into account Section 5.3(b) and Section 5.4, Terra would be
                  entitled to rely on the failure of a condition set forth in
                  Section 5.3(a) as a reason not to complete the Transaction);
                  or

            (vii) be terminated by Terra if the Optimal Meeting has not occurred
                  on or before the Optimal Meeting Date (unless the condition
                  set forth in Section 5.2(a)(iv) is not satisfied or Terra
                  shall have made a misrepresentation at the date hereof or
                  breached a covenant under this Agreement in such a manner
                  that, taking into account Section 5.2(b) and Section 5.4,
                  Optimal would be entitled to rely on the failure of a
                  condition set forth in Section 5.2(a) as a reason not to
                  complete the Transaction);

      in each case, prior to the Effective Time.

      (d)   If the Effective Date has not occurred on or prior to the Outside
            Date, then, unless otherwise agreed in writing by the Parties, this
            Agreement shall terminate provided that the right to terminate this
            Agreement pursuant to this Section 6.2(d) shall not be available to
            the Party seeking to terminate if any action of such Party or its
            Affiliates or the failure of such Party or its Affiliates to perform
            any of its obligations under this Agreement required to be performed
            at or prior to the Effective Time shall have resulted in the
            conditions contained in Section 5.1, Section 5.2 or Section 5.3 (as
            applicable) not having been satisfied prior to the Outside Date.

      (e)   If this Agreement is terminated in accordance with the foregoing
            provisions of this Section 6.2, no Party shall have any further
            liability to


                                      -65-
<PAGE>

            perform its obligations under this Agreement except as provided in
            Section 6.3 and as otherwise expressly contemplated by this
            Agreement, and provided that neither the termination of this
            Agreement nor anything contained in this Section 6.2(e) shall
            relieve any Party from any liability for any breach by it of this
            Agreement, including from any inaccuracy in its representations and
            warranties and any non-performance by it of its covenants made in
            this Agreement.

6.3   Break and Other Fees

      (a)   If:

            (i)   Optimal shall terminate this Agreement pursuant to Section
                  6.2(c)(iii);

            (ii)  Optimal shall terminate this Agreement pursuant to Section
                  6.2(a) and an Acquisition Proposal has been publicly made,
                  publicly announced or otherwise publicly disclosed by any
                  Person other than Optimal prior to the Terra Meeting and has
                  not been withdrawn before the Terra Meeting; or

            (iii) Terra shall terminate this Agreement pursuant to Section
                  6.2(b) or Section 6.2(c)(iv), in each case, in circumstances
                  where the requisite Terra Shareholder approval has not been
                  obtained, and an Acquisition Proposal has been publicly made,
                  publicly announced or otherwise publicly disclosed by any
                  Person other than Optimal prior to the Terra Meeting and has
                  not been withdrawn before the Terra Meeting;

      then in any such case Terra shall pay to Optimal the Break Fee in
      immediately available funds to an account designated by Optimal. Such
      payment shall be due within one Business Day after demand by Optimal.
      Terra shall not be obligated to make more than one payment pursuant to
      this Section 6.3(a).

      (b)   If Terra shall terminate this Agreement pursuant to Section
            6.2(c)(iv), other than in the circumstances described in Section
            6.3(a)(iii), then Optimal shall pay to Terra the Break Fee in
            immediately available funds to an account designated by Terra. Such
            payment shall be due within one Business Day after demand by Terra.

      (c)   If Optimal shall terminate this Agreement pursuant to Section
            6.2(c)(vi) or if the Terra Shareholders shall fail to approve the
            Transaction at the Terra Meeting (unless the condition set forth in
            Section 5.3(a)(iv) is not satisfied or Optimal shall have made a
            misrepresentation at the date hereof or breached a covenant under
            this Agreement in such a manner that, taking into account Section
            5.3(b) and Section 5.4, Terra would be entitled to rely on the
            failure of a condition set forth in Section 5.3(a) as a reason not
            to complete the Transaction), then, except in the circumstances
            contemplated


                                      -66-
<PAGE>

            in Section 6.2(c)(iv), on the first Business Day following the
            termination of this Agreement as a result thereof, Terra shall pay
            to Optimal $500,000 as payment in full of Optimal's out-of-pocket
            costs and expenses in connection with the Transaction in immediately
            available funds to an account designated by Optimal. Any payment due
            under Section 6.3(a) shall be reduced dollar for dollar by any
            payment previously made under this Section 6.3(c).

      (d)   If Terra shall terminate this Agreement pursuant to Section
            6.2(c)(vii) or if the Optimal Shareholders shall fail to approve the
            Optimal Resolution at the Optimal Meeting (unless the condition set
            forth in Section 5.2(a)(iv) is not satisfied or Terra shall have
            made a misrepresentation at the date hereof or breached a covenant
            under this Agreement in such a manner that, taking into account
            Section 5.4, Optimal would be entitled to rely on the failure of a
            condition set forth in Section 5.2(a) as a reason not to complete
            the Transaction) then, except in the circumstances contemplated in
            Section 6.3(a) above, on the first Business Day following the
            termination of this Agreement as a result thereof, Optimal shall pay
            to Terra $500,000 as payment in full of Terra's out-of-pocket costs
            and expenses in connection with the Transaction in immediately
            available funds to an account designated by Terra. Any payment due
            under Section 6.3(b) shall be reduced dollar for dollar by any
            payment previously made under this Section 6.3(d).

6.4   Remedies

      The Parties acknowledge and agree that an award of money damages would be
inadequate for any breach of this Agreement by any Party or its representatives
and any such breach would cause the non-breaching Party irreparable harm.
Accordingly, the Parties agree that, in the event of any breach or threatened
breach of this Agreement by one of the Parties, the non-breaching Party will
also be entitled, without the requirement of posting a bond or other security,
to equitable relief, including injunctive relief and specific performance. Such
remedies will not be the exclusive remedies for any breach of this Agreement but
will be in addition to all other remedies available at law or equity to each of
the Parties.

                                    ARTICLE 7
                                     GENERAL

7.1   Notices

      Any notice, consent or approval required or permitted to be given in
connection with this Agreement (in this Section referred to as a "Notice") shall
be in writing and shall be sufficiently given if delivered (whether in person,
by courier service or other personal method of delivery), or if transmitted by
facsimile or email:


                                      -67-
<PAGE>

            (a)   If to Optimal, at:

                           4700 de la Savane
                           Suite 101
                           Montreal, Quebec
                           H4P 1T7

                           Attention:        Holden L. Ostrin
                           Telecopier No.:   (514) 738-8355
                           Email:            holdeno@opmr.com

                  with a copy to:

                           Osler, Hoskin & Harcourt LLP
                           1000 de La Gauchetiere Street West
                           Suite 2100
                           Montreal, Quebec
                           H3B 4W5

                           Attention:        Warren M. Katz
                           Telecopier No.:   (514) 904-8101
                           Email:            wkatz@osler.com

            (b)   If to Terra at:

                           2 Place Alexis Nihon
                           Suite 700
                           3500 de Maisonneuve Boulevard West
                           Westmount, Quebec
                           H3Z 3C1

                           Attention:        Mitchell A. Garber
                           Telecopier No.:   (514) 380-2768
                           Email:            mitch@terrapayments.com

                  with a copy to:

                           Stikeman Elliott LLP
                           1155 Rene-Levesque Boulevard West
                           40th Floor
                           Montreal, Quebec
                           H3B 3V2

                           Attention:        Sidney M. Horn and Peter Castiel
                           Telecopier No.:   (514) 397-3222
                           Email:            smhorn@stikeman.com
                                             pcastiel@stikeman.com


                                      -68-
<PAGE>

      Any Notice delivered or transmitted to a Party as provided above shall be
deemed to have been given and received on the day it is delivered or
transmitted, provided that it is delivered or transmitted on a Business Day
prior to 5:00 p.m. local time in the place of delivery or receipt. However, if
the Notice is delivered or transmitted after 5:00 p.m. local time or if such day
is not a Business Day then the Notice shall be deemed to have been given and
received on the next Business Day.

      Any Party may, from time to time, change its address by giving Notice to
the other Party in accordance with the provisions of this Section.

7.2   Assignment

      Neither this Agreement nor any rights or obligations under this Agreement
shall be assignable by any Party without the prior written consent of the other
Party, except that Optimal may assign all or part of its rights or obligations,
including the rights to acquire the Terra Shares, without reducing its own
obligations under this Agreement, to a wholly-owned Subsidiary. Subject to the
previous sentence, this Agreement shall enure to the benefit of and be binding
upon the Parties and their respective successors (including any successor by
reason of amalgamation of any Party) and permitted assigns. No third party shall
have any rights under this Agreement unless expressly stated to the contrary.

7.3   Further Assurances

      The Parties shall with reasonable diligence do all such things and provide
all such reasonable assurances as may be required to consummate the transactions
contemplated by this Agreement, and each Party shall provide such further
documents or instruments required by any other Party as may be reasonably
necessary or desirable to effect the purpose of this Agreement and carry out its
provisions.

7.4   Expenses

      Subject to Section 6.3, the Parties agree that all costs and expenses of
the Parties relating to the Transaction and the transactions contemplated by
this Agreement, including legal fees, accounting fees, financial advisory fees,
regulatory filing fees, stock exchange fees, all disbursements of advisors and
printing and mailing costs, shall be paid by the Party incurring such expenses.

7.5   Public Notices

      All public notices to third parties and all other publicity concerning the
transactions contemplated by this Agreement shall be jointly planned and
co-ordinated by the Parties and no Party shall act unilaterally in this regard
without the prior approval of the other Party, such approval not to be
unreasonably withheld, unless such disclosure shall be required to meet timely
disclosure obligations of any Party under applicable securities Laws and stock
exchange rules in circumstances where prior consultation with the other Party is
not practicable.


                                      -69-
<PAGE>

7.6   Execution and Delivery

      This Agreement may be executed by the Parties in counterparts and may be
executed and delivered by facsimile and all such counterparts and facsimiles
shall together constitute one and the same agreement.

      IN WITNESS WHEREOF the Parties have executed this Combination Agreement as
of the date first written above.

                                            OPTIMAL ROBOTICS CORP.


                                            By:  /s/ Holden L. Ostrin
                                                 -------------------------------
                                                 Authorized Signing Officer


                                            By:  /s/ Neil S. Wechsler
                                                 -------------------------------
                                                 Authorized Signing Officer



                                            TERRA PAYMENTS INC.


                                            By:  /s/ Mitchell A. Garber
                                                 -------------------------------
                                                 Authorized Signing Officer


                                            By:  /s/ David Schwartz
                                                 -------------------------------
                                                 Authorized Signing Officer


                                      -70-