The use of Semantic Web Service (SWS) technologies have been suggested to enable more dynamic B2B integration of heterogeneous systems and partners. We present our approach to accomplish dynamic B2B integrations based on the WSMX SWS environment. We particularly show how WSMX can be made to support the RosettaNet e-business framework and how it can add dynamics to B2B interactions by automating mediation of heterogeneous messages. This is illustrated through a purchasing scenario. The benefits of applying SWS technologies include more flexibility in accepting heterogeneity in B2B integrations and easing back-end integrations. This allows for example to introduce more competition into the purchasing process within e-business frameworks.