If you create a motion menu background (even if it's a still picture) you can have the video for the menu fade in. Just bring your background pic into VMS, set up a fade in and render it out to an AVI/NTSC DV file (DVDAS will re-encode the file if its MPEG-2, so I usually just render to AVI for menus).

Then to get the buttons to appear after you have faded in, check the DVDAS 3 (or later) help file for "Setting Loop Points for Menus"

--Scott