Here is the wiring diagram that I have. It is for the installation of the MPSS (source selection device). Basically what I did initially was the same as the diagram with the MPSS removed and the CD-Changer audio simply disconnected (pins 18, 19 and 20).

Short instructions:

1. Cut off and discard the blue portion of the plug from the CD-Changer
2. Cut off and discard the green portion of the plug from the iPod adapter.
3. Connect the green wire from the iPod connector to pin 9 (black wire on the green plug from the CD-Changer cable)
4. Connect the gray wire from the iPod connector to pin 8 (thicker red wire on the green plug from the CD-Changer cable).

Now you have your 'cheater' iPod cable.

Cheers!