How to assign From one NS to another NS in a BPEL?

Hi -

My BPEL calls an EJB, and I want to assign part of the EJB's result into the returned value of the BPEL.  The fragment I'm interested in occurs one or more times and is a complex type with optional elements.  The problem comes in because the EJB's result in in a different namespace from the BPEL's result that I want to copy into.  Just assigning the fragment leads to a selection failure at runtime.  But I can't assign the pieces individually, even in a loop, because of several optional elements that may not be there.

How can I assign this fragment in a way that changes it's namespace to that of the output value?

What I need is some sort of cast?

Thanks!