HELP with scrolling buttons that load .jpgs in MC

If you visit this site and once you are in go to “Conciertos” you’ll see a list of dates, everytime you roll over one of them an image is shown. As I’m running out of space I have to place those buttons (the dates) inside a scroll. I’ve been trying to do that but, once the buttons are inside a scroller as a MC, they just don’t work. It seems the action of the buttons is on different place than the Container MC, but I dont know how to relate them. How can I do it???