There are migration tools between jPDL and BPMN2 but I don't not recommend that option. If you are planning to migrate now you should migrate to BPMN2 directly, because there is no one to one transalation between the jPDL and BPMN2 node semantics. If you are planning to migrate from aqua logic to jPDL you will need to refactor your processes, the same will happen when you want to migrate to BPMN2. If you are planning to do process refactorings just save yourself one round and go ahead with BPMN2.
Cheers