Yesterday I came across William Vambenepe's blog post: BPMN to BPEL: going to battle with one hand tied? It shows that if you translate a simple BPMN model to BPEL, the BPEL process is not really recognizable any more. It seems to reconfirm my initial estimations about that kind of transformation.
I'm happy with the rapid adoption of BPMN in the BPM world. But I was always puzzled by the big focus of the BPMN to BPEL conversion. I have not done the excercise myself of trying to write an algorithm that did such a transformation because the models just don't seem to fit. BPEL is a composite (aka block) structured language. BPMN is graph based. BPMN is focussed on process analysis, while BPEL is about orchestrating web services. And in my experience, the non tech business analysts don't think in terms of web services.