Help with audio on Virtualdub capture

I'm not exactly a newbie but am having a problem. I am attempting to convert old VHS to DVD. I have my VCR hooked up to a Sony Digiital 8 camcorder (with TBC) which then connects to my PC via Firewire. I have windows XP and of course plenty of hard drive space and a freshly defragged drive. I have been using Pinnacle Studio to capture but keep running into nagging sync issues after about an hour of capture. I get ZERO dropped frames using this process which is great. I decided last night to try using Virtualdub to capture instead to see if that would solve my sync issues. However, when I capture, it picks up the video just fine but is not recording the audio AT ALL. There must be some setting that I must not have set properly but I can't find it. Perhaps Virtualdub is looking at my soundcard for the input rather than the firewire but I'm not sure.
Many thanks for any help you can provide.