FYI it would be nice to have an example where the process calls an external webservice (not packaged within the process)....
BPEL process definitions rely on WSDL abstract definitions (messages and port types) only. Just as in EJB development, the involved parties agree on a service interface; each party gets a copy of the interface documents and starts working separately on getting their side working.
Pointing to a deployed document from bpel-definition.xml is possible, but inconvenient for the very reason you mention. A better practice is downloading the document and removing the binding and service elements.
In the case of bpel-application.xml, you need a registry (such as a UDDI server) to shield you from changes in the partner endpoint addresses. That's in our roadmap but not available yet.
I thank you for your help... i updated it with a local wsdl and it worked fine....