Its all about the bones.
They both use there own bone sets. So if you used a human animation on a droid, the droid would look messed up. Vice versa for the clones/ humans. The wookies also have there own bone set. The females always puzzled me, it says there scaled, but on the view, there bones match there model.
You would need the proper XSI, then you could build your own bones. Then evelope the bones to the model. Then export it. LOL!!