CD changer adapter cable to mp3 player

I've got my personal mp3 player installed in a decent looking cradle, in my B5 (99) A4. Problem is I'm running the output of it into a tape adapter for my concert 1 headunit (which sounds totally cr4p because of the hiss etc etc). Does anyone know a good UK supplier where I can get a cd changer lead (as found in the boot of B5 A4s) to a phono/audio adapter to fool my headunit into thing the autochanger is attached and to run the output of my mp3 player into it.

I've found a site based in the states but the price with shipping makes it almost cheap enough to get an mp3/CD Headunit (which I don't want..... long story involing diabloical radio recepetion)

Cheers

Not to worry... Found a place in Leeds who can get me one for £85 all in. The shop's called Unicar. Has anyone used this place before ?