Web services depend on XML documents that can be understood by the parties (or applications) that wish to do business, which requires that they agree on the meaning and organization of the information elements the documents contain. Without an agreement on an XML vocabulary, the glib promises of easy integration and interoperability with web services are undermined by the need for custom coding to transform instances of one side's data model into the other's. In this paper we discuss methodological and design issues that emerged in our work with the Talaris Services Business Language™ (SBL), an XML vocabulary developed to make it easier for suppliers of business services to integrate with a Talaris application that is used by corporate employees to purchase business services on the Web. Talaris chose to use the emerging Universal Business Language (UBL), a horizontal XML vocabulary of common semantic components, as a basis for SBL to give it more robust semantics and to encourage its adoption.