Business-to-business (B2B) Electronic Business (EC) is speedily getting popular and companies are increasingly using this notion and technology for business transaction and data exchange among each other. Traditionally, using Electronic Data Interchange (EDI) on Value Added Network (VAN) is common for data exchange on B2B EC, however drawback are the trade-off between flexibility and efficiency among partners in the whole supply chain; cost is often an issue due to the lack of standard in information exchange. Now, the popularity of XML (Extensible Markup Language) helps companies to solve the problem because of its economical cost and flexibility. In this paper a model for data exchange is investigated so that the cost for information flow could be reduced and the flexibility of the supply chain could be improved.