Some BPM platform from other software vendors using the XPDL standard are being phased out. Now that BPMN also allows execution with the version 2.0 I built a converter that takes any XPDL file (1.0 or 2.1) and converts it to BPMN 2.0 including gateways, subprocesses, data, lanes. I also handle some specific vendor extensions (forms, scripts).
I used JAXB on the standard schemas for the processing.
Then I load the resulting BPMN 2.0 in the Rational Software Architect BPMN Editor or IBM Business Process Designer.
The following image shows some of the correspondance between the process definition standards, however that correspondance needs real Java progamming. XSLT is not enough.