I'd assume it'd be in the mesh files, more specifically the .skeletonmesh files. How would we change the data in the .skeletonmesh files? What'd it look like to us? We could, for example, take the original file, manipulate it in a modelling program, save it, note the differences within the files and manipulate the upk from there. It might also be a good idea to manipulate one vertex at a time. I think the solution will still be just to copy the differences from a modified file, but it'd be nice to find some method in this madness.