This may be an incorrect setup issue but ....

I notice that livetv sounds come directly out of my soundcard. My recording sounds are delivered out of the pvr-350. It seems simple to patch the output from the pvr thru the line in to get all the sound coming out of the soundcard. However, I'm not getting any sound from the line-in. Is there some configuration trick I'm missing here? It's kind of like the line-in is "muted". TIA for help.

Your line-in is probably muted. I use 'aumix' to adjust my line-in.