Strumming a guitar string

Hi, I’m having an issue with my flash program. What I want to do is allow the user to move the mouse over a guitar string and it will bend back and forth. I’ve made the movie clip and that looks good, but I’m having an issue trying to make it work. I tried making a button and just putting the movie clip in the over frame, but the movie clip immediatly stops when the mouse is no longer hovering over the string. How can I make it so that when the user’s mouse goes over the string the movie clip plays and doesn’t stop until the last frame of the movie clip?

Thanks.