Vibration Effect Tutorial Help

Hi,

I followed the tutorial for the Vibration Effect which can be found at http://www.kirupa.com/developer/mx/vibrate.htm. It worked perfectly, my problem is that I want to make it into a button so that it only vibrates when the mouse hovers over it. But when I try to do this it stops vibrating all together.

Hope someone can help me with this problem.

Thanks in advance,
Donna