I think this must be a crucial issue for jbpm because next version of a soa platform must include jbpm5. It's not real to go on working with jbpm3 in soa jboss projects.
So IMHO jbpm5 must provide a handler to call a esb service in a synchronous way and in an asynchronous way (service orchestration)
From esb side, jboss esb must be able to start,stop,signal a jbpm5 process
jbpm5 in a soa fashion must provide a taklist web application that can be easily customized for customer needs (for example provide a maven profile to build a tasklist webapp with the logo of company and with specific css)
Giovanni