Hi,
don't know if you noticed, but WPS 1.0 final spec is out:
http://www.opengeospatial.org/standards/wps
and the 52n implementation of it is ready too:
http://sourceforge.net/project/showfiles.php?group_id=183259
https://incubator.52north.org/twiki/bin/view/Processing/52nWebProcessingService
Now, I don't have personally time to track this down, but
it would be nice if somebody had a look at it.
Cheers
Andrea