To make that type of menu (thumnail videos on a still or video background) you need to use another program (an NLE or compositer, such as After Effects) to composite the video clips together and then encode the finished video as MPEG2. You then import the video as the background layer of the menu. The subpicture overlay will need to be a 2-bit red/blue/black/white still image. This is what the DVD spec supports.
Tyler A. Hawes
Audio Intervisual Design
18 Years Integrating for Film, Television, DVD & Music Production
West Hollywood, CA: (323) 845-1155