Your sync most likely will be off between your multi track audio recording and your cam's capture.
Load your cam's capture in your audio project. If it's not in sync, stretch/shrink (Ctl + drag the end) the video to match the audio. Video is much more forgiving than audio.
That's as specific as I can be given your details.
Thanks for your reply.
Im looking for a real time method. Example, I can record live music on multiple tracks in vegas but cant record video in vegas. I would like to be able to record video to pc via analog capture card and record multi audio, to vegas, realtime.
Yes you can use Vidcap to capture your A/V signal via a firewire port while at the same time using Vegas to record multiple audio tracks from a sound card.