Spell which has applying of M2 model on correct bone of model as visual effect might do. Don't ask me how to do it, I don't know (well, I have a feeling how to do it, but I am not entirely certain). Its just a possible way out. For instance, check spell which applies warsong flag on your back. It literaly spawns warsong flag model on bone in back of character model and bounds that model to it. You might need to do something similiar, but with some bone in head instead.
