I'm sure this isn't what the jBPM team recommends. Surely they recommend using one version of the built-in editors, since they're actually included in the system. The docs don't saw "just use someone else's editor". I was also unsuccessful in building executable processes using the BOMN2.0 editor, so I just suspect it's "not ready for primetime" yet. What business processes can you not model?
I'm interested in what one of the developers has to say about this...