Using MC as 'Over' on Button...MC stops on Rollout...h

like the title says, i have a button which has a blank up frame, has an instance of a MC which shimmers. it works great, however when i rollout in the middle of the MC playing, it stops. is there a way to get this to play out?

http://s170193323.onlinehome.us/MKPortalSMF/index.php

Roll over EXTREME, once you see that, do it again and rollout before it finishes its shine.

tia.