We can easily put together a batch file to rip and do the conversion. However, a more optimal solution would be to get a correct WMA header to add to the raw xWMA's. As I understand it xWMA's are pretty much the same as a normal WMA and should work as part of a WMA container.
I'm going to keep trying to do this, if I can get a container then I can easily make an app to read the soundbanks and put the data in a RIFF/WMA container. Its a shame that the WMA format is such a pain in the arse¬