I have just completed a project using a motion menu, this may be redundant to you but here are some things I encountered that would have been helpful if I had known them before hand.
1. You need to create a static version of your menu first as the background image, and then hide all layers that are not buttons before linking your motion menu.
2. Make sure to render out your motion menu as an .avi file.
3. If the motion menu does not play during the preview, you need to go to File then Render Motion Menu.
I experienced some bugs in the program when you start confusing it with menus, so I guess the less you mess with it the less problems you will have.
Good luck!