Interoperability in service oriented environments is heavily inuenced by the view that the cooperating services have on their data. e term service for the abstract contract concluded between a service requester and a service provider, three dierent data schemas have to be identied, namely the requester's schema, the provider's schema and the reference schema introduced by the service specication. Metamodeling and schema transformation approaches from the area of model driven architecture can be used to dene these schemas and their mappings as well as the appropriate transformations that have to be applied to the data. This paper explains an approach towards metamodelbased service interoperability along an extended example of providing visualization services for the Bauhaus re-architecting tool. 1 Motivation and Related Work Interoperability is the challenge of enabling software tools from dierent suppliers to share their functionality. Coupling dierent, but interopera...