This is possible thanks to a flexible framework allowing extensible views, model and transformations, that communities and vendors can build on. JWT comes with several built-in extensions like UML Activity Diagram or Event-driven Process Chains (EPC) views, BPMN interoperability, code generation (e.g. XPDL, or WSBPEL-code in the AgilPro integration, but also HTML documentation). There are actually already a few solutions that integrate JWT, such as the SOA-focused Scarbo of the OW2 consortium, or AgilPro in SourceForge.
JWT is available in Galileo using Help -> Install New Software... -> Galileo -> General Purpose Tools -> Java Workflow Tooling (Incubation).Come and get it!