hello Folks,
My first ever post anywhere, so go easy. I had a similar problem and did the following
1 - Get a cable with headphone jack on one end and right/left Phono on the other.
2 - cut off the phono jacks and splice the right and left wires into the cable running between the cd unit and the head unit.
3 - get a blank cd and create a music track thats 79 minutes long and totally silent, i inserted this cd in the sixth slot of the cd player.
i used a music editor programme on a pc, got an existing track, stretched it to 79mins and then reduced the volume to 0. there may be easier ways of doing this
In order to play the mp3 player i just select cd6. The unit is still connected to the cd player but the sound comes from the mp3.
The quality is excellent. From memory the cables to connect to were yellow and black (2 wires) and pink or purple and black (2 wires).
You can access these beneath the seat and test by holding the wires in place without disconnecting the wires, but carry out the final connection behind the radio.
This works fine for me and solved the problem of connecting an mp3 player without upgrading the radio or losing the steering wheel control,
Hope this is clear, i wont claim to have any techincal knowledge and would appreciate comments from anyone who does, let me know if you need further info.
Regards
Tony