Check post #8065, you may have done this already. I can confirm that with a few mods the ttr225 wheel will fit an xt225. If the hubs share the same parts numbers on the ttr230 and ttr225, and the xt225 and tw200 share the same exact rear hub, then indeed, you are in business. Just check the parts fiche on one of the mailorder places (Cheap Cycle Parts, etc.) for parts #'s. #8065 has a link to an earlier post that describes the process in more detail if they do indeed match.
Keep us in the loop.