Hey
I dont have a Canon, but a JVC dv cam and converted some old videos through iMovie last week.
U need to have a scart that 'outputs' to your camcorder, not input. I have a scart end [just the scart connector box, without a lead coming out], that lets me plug the white, yellow and red plugs into which has the analogue camcorder connector on the end. On the side there is a switch - output or input. Switch to output. Plug firewire from camcorder to my Powermac and hey presto - can see whatever is playing on video.
Just a case of capturing the footage and let the video play through.
Make sure u have the settings correct on your camcorder too, as i had to set it on 'play mode' and manually adjust a menu so that input was from an anologue connection.
Think Canon have to be set to vcr mode?? Check your input settings if u can?
Good luck.