If you check out JBossESB 4.2MR, there's a quickstart in there called webservice_bpel that illustrates what you're looking for. We're working on improving these capabilities in the 4.2GA codebase, but we're not there on that yet (so don't try that quickstart from SVN trunk).
Also check out the flash demos here.
Great, thank you! is it necessary to set-up a JMS queue for a web service to web service pipe as in the bpel example?
In the current architecture, yes. The SOAP message is received via what's called a "Gateway Listener". It's job is to receive the message, "normalize" it into an ESB Message structure and forward it to a Message Aware ActionProcessing pipeline which performs the actual message payload processing before routing the message, in it's new format, to the target Service (i.e. SOAP to RMI call in this case).
At the moment, the only options for performing the Gateway->ActionProcessingPipeline routing is over the likes of JMS (see message couriers), but I think there may be an local-vm type option planned.