Starting and stopping rotation

I’m relatively new to flash, and I’ve run into a few problems. What I’m trying to do is have a four buttons that continuously rotate around an unfilled circle. I’ve got the rotation down using the following code in three successive keyframes:

setProperty (“circle”, _rotation, r); r=r+1;

When you the user mouses over one of the buttons, I need the rotation to stop, and have an animation scroll in from the right side of the screen. When the user removes the mouse from the button, I need the animation that scrolled in to scroll back out, and have the circle start rotating again from the exact spot that it stopped. If any of you have any suggestions on the best way to accomplish this, I would appreciate it.