Problems with attachmovie and animation

Hi, Im trying to make a ‘game’ where you have a character selection, and use that character in the rest of the game. I tried to use the attachMovie function on an empty movieclip, this works, but when I try to animate the empty movieclip using motion tween I got problems.
At the time I just allow the user to choose between same sized/formed movieclips. So I animate on one of these, and attach the movieclips over this one. This clearly being a temporary quick fix.

There surely is some good way to implement this, guys?.