I have a similar set-up with a DVD2 and a V8000 connected to a Beocenter 6, with the DVD2 registered as DVD and the V8000 registered as V-MEM. While I can record from DVD2 to V8000, it doesn't seem possible the other way round. If I start a tape on V8000 and then switch to DVD2 to record it, the playback on V8000 automatically stops immediately. This is a little bit frustrating.
However, in your case it looks more like a technical problem as you are still able to record the picture.
There does not seem to be many users of both DVD2 and V8000 on this forum, so we are probably bound to get to our B&O dealers for help.
BV7-40, BC6-26, DVD2, BCordV8000, BS4, BS2, BS Ouverture, BC9500, BM8000, BCord9000, BL8000, BL6000, BL2, BL3, BVox4500, BCom6000, Beomedia1, BCom5, Serenata