Abstract In this paper we present how Semantic Web Service technology can be used to overcome process and data heterogeneity in a B2B integration scenario. While one partner uses standards like RosettaNet for product purchase and UNIFI ISO 20022 for electronic payments in its message exchange process and message definition, the other one operates on non-standard proprietary solution based on a combination of WSDL and XML Schema. For this scenario we show the benefits of semantic descriptions which are used within the integration process to enable rulebased data and process mediation of services. We illustrate this dynamic integration process on the WSMX