Cannot capture VHS video in iMovie 09

I'm trying to digitise several (as in about a hundred) VHS tapes, but I've run into two problems before I've even begun.

I've got two major problems; The first being iMovie 09 won't capture VHS from my VCR (but it will capture analogue output from a DVD recorder) and the second is iMovie isn't giving me any video/audio preview when capturing video.

I've connected my VCR to the Canopus ADVC 100 ports on the front of the box via a scart to RCA composite cable. Then I've connected the ADVC to my MacBook Pro (Snow Leopard, 10.6.6) via the 4-pin FireWire port on the front to my Macs' 9-pin Firewire 800 port using a 6-pin to 9-pin adapter.

When I switch on the ADVC, iMovie detects it and properly names it in the "Camera" drop-down box and opens the capture window with a blue screen. Sometimes (if I've just opened iMovie and this is the first capture I've done) it says "Play" in the top left hand corner of the preview. Since this is the first time I've used any analogue-digital hardware and iMovie, I'm not sure whether this is significant or not.

If I try to capture footage by clicking the "import" button, whether my VCR is playing or not, iMovie says it is recording (the red recording dot appears in the timer) but the timer does not start counting, as if it knows there is no signal and thus nothing to capture. Nothing is captured when I stop the import. I've tried two different VCRs but couldn't capture from either.

However, if I capture DVD video from my DVD recorder (using a different composite cable to connect the RCA inputs on the front of the ADVC to my DVD recorders' RCA outputs), the capture works (the timer increments), but there is no audio or video displayed in the iMovie preview window. I've read in other threads that there will be no audio because this is apparently not supported as of iMovie 06+, but I've not read anything definite about there being no video preview. So this is my second problem – no preview available – just a blue screen.

I've also tried plugging the yellow RCA video plug into a RCA video – S-Video (7-pin) adapter cable and plugging that into the 7-pin S-Video "Video in" input on the back, but that made no difference to anything. I've tried using a different 4-pin to 6-pin Firewire cable (with the same aforementioned 6-pin to 9-pin adapter) but didn't make any difference either.

My DIP switch settings are 1 = ON (I'm trying to capture PAL VHS video recorded on PAL VCRs and iMovie is set to PAL as well) and the rest are set to OFF.

My Mac is able to detect the ADVC (it appears under "Firewire bus" in the System Profiler when it is powered on).

One last point to make – the only VCRs I have available are the kind which are integrated into the TV unit, i.e. a TV-VCR combi unit. Would using a standalone VCR make a difference?