Factory In-Dash Changer with Aftermarket Deck?

Hey guys, I just finished installing my Eclipse CD5000 and it's worth every penny. My car came with the premium sound system, so I was wondering if I could somehow keep the in-dash changer? I tried plugging it into the back of my new deck, but it doesn't seem to want to work? Is the changer only compatible with the factory head unit, or is there some trick to get it to work with aftermarket decks? Thanks, I'd love to get them both working!