I'm almost 100% sure that that only works with ATI cards.
Alot of Nvidia cards have adapters from an s-video looking connector to component. The only difference is that ATI was more clever with where they used extra pins.
I've never read a post where someone was able to use one of these adapters successfully with another video card, but many who realized that their non-ATI (and even many ATI) cards were not compatible.