Greetings folks

I have a Canon ZR-40. I have a VCR hooked up to it so the ZR40 converts the analog signal to digital. I see the vid on the ZR40 and when I go to the vegas capture screen and capture the video it starts playing the DV tape in it. WHen I hit stop on the ZR40 i see a half a second of the VHS signal in Vegas but it then stops. How can I capture straight through to Vegas?

Thanks
Jack