G3 + PCI video card = no A/V card?


I'm Spartacus!
Has anyone out there run into the same following problem? Has anyone gotten this kind of setup to work fine?

I upgraded my Beige G3 from onboard video to a PCI video card. (Radeon 7000, 64MB). Now when my monitor is plugged into that card, my A/V card won't capture any kind of video. Apple video player and BTV pro start thinking the drivers for the A/V card aren't properly installed and receive no signal from the A/V card.

I've been told that this is because my video card has flashed ROM and that the A/V card requires specific video card hardware to run properly. Is that what it is? Does the A/V personality card just not work with PCI video card upgrades? Does the A/V card have to be using a Rage video chipset or lower to work?

Please, help would be much appreciated. It has proven quite difficult to get an answer for this problem so far. Thank you in advance. :)