Pausing a MC on mouseover

I am creating a moviclip that consists of 20 thumbnail images scrolling horizontally. I want to make the movie pause when you put your mouse over an image and have that image enlarge. I am thinking that the images can be created as buttons with the "over" state being the enlarged image, but how do I get the MC to stop scrolling? The movie clip will continue scrolling on mouseout. I am not planning on having any control for the speed or direction of the MC, just a set scroll speed by using a motion tween. This MC will be placed as an instance another page. Any help would be appreciated! BTW I am using Flash 5.