What kind of converter did you get to get everything set up?
The exact same one Christuserloeser linked to. The RGB signal from the Genesis is transmitted through a SCART cable, which connects to this converter which then outputs to component. Using this setup, the Genesis displays 240p and the Saturn will alternate between 240p and 480i resolutions (usually menu screens are in 480i, and in game content is in 240p).
I had to modify the Genesis RGB-SCART cable that I bought off of ebay, because it was using composite for the sync signal. Because of this, I had a jail-bar effect on solid colors. So I took the cable apart and connected the sync direct using a 90 ohm resister. Problem solved.