rng 2 xmi

Is anyone aware of code that will transform RNG to XMI (and vice versa)?


Some background on the question. I need to be able to publish schemata
as RNG, WXS, UML and where appropriate, DTDs. I want to pick one form as
canonical for editing and generate the others from it. The canonical
documented form is UML, but the ideal  editing setup would be to work in
RNG and publish as XMI/WXS. 

If such a thing doesn't exist, would anyone else use it?

regards,
Bill de hÓra
..
Propylon
www.propylon.com