Actually, a better way to do the versioning is on the deployment phase.
say you have an bpel artifact, hello_world.jar that contains bpel process files etc. With renaming this jar into hello_world-1.jar into the JBoss AS's deploy folder, it will recognise this artifact version as '1'. Now, if you want to update the version, you could simply name it hello_world-$version.jar.
Also, say if you deployed the same name artifact, the previous version of that artifact will become 'retired'.
I think this is the recommend way to do bpel/process versioning.