Business processes not only play a key role in business-to-business and enterprise application integration scenarios by exposing the appropriate invocation and interaction patterns; they are also the fundamental basis for building heterogeneous and distributed applications (workflow-based applications). Business Process Execution Language for Web Services (BPEL4WS) provides the means to specify business processes that are composed of Web services as well as exposed as Web services. Business processes specified via BPEL4WS are portable; they can be carried out by every BPEL4WS-compliant execution environment. In this paper we show how the IBM J2EE™ application server, WebSphere® Application Server provides such an environment, called process choreographer environment, and how the extension mechanism built into BPEL can be used to leverage the additional capabilities of J2EE and WebSphere.