1997 vw golf auxillary input

My friend would like to hookup her portable MP3 player to the factory stereo and I refuse to use an FM Modulator as the quality is so poor from those. I haven't yet looked at the back of the stereo, but supposedly this stereo can interface with a factory cd changer. That being the case, is there a simple cable adapter that will establish an audio input path into the stereo so that I may hookup a line level source? I know on one of my own stereos I was able to get a $10 cable that had a din connection at one end and RCA's at the other. I imagine it had a resistor or something across two pins on the din to make the stereo think an actual CD Changer was connected. I'm hoping this is true with the VW, but haven't been able to find any solid information.

It is usually more than a resistor across 2 pins that allow the radio to switch to the changer.  I am not sure about the VW radios, but most of the other units that are able to use the changer input for an aux in, require a box with a microprocessor inside that communicates with the radio.  It has to handshake with the radio.   Peripheral and soundgate are the 2 companies that come to mind when looking for such adaptors.

Anyone have an idea if it's just a simple cable or a module with some sort of electronics?