Dunno much bout AV stuff but I have got my Wii running through my stereo...
I just split the cable component cable (Think thats its name - the one with red white and yellow plug things) so I could get the yellow one in the scart adapter going into the TV and the audio ones to my amp.
If you dont have your TV near your amp just by a good quality extension cable with femal to male ends.
Not sure how that works if your using hidef though.
Sounds wicked when you crank up red steel!!!