Duane: This looks like what you need http://www.planetnautique.com/index.php?name=PNphpBB2&file=viewtopic&t=1696
After some research, I couldn't believe that it was impossible to set up an input on the XMD1. I found a schematic and provided the information necessary to make it work. We have been using it since June, and it works like a champ! I will attempt to walk you through the setup as I have done it, and hopefully you can be enjoying lots of tunes...
First off, you will be interfacing to the CD Changer port. This is a goofy 13 PIN DIN, and these connectors are semi-difficult to track down. You can get one for 4.99 plus shipping from: http://www.universal-radio.com/catalog/parts/dinconn.html
Then you need to get out your soldering iron, hehe, and follow the schematic... I will try to tell you how this works if you aren't familiar with schematics...
Here is the schematic:
There are lots of ways to go about this, but I picked up a female headphone plug and matched up the tip pin (Right Positive) with Pin 8 on the 13 PIN plug, matched up the inner pin (Left Positive) with Pin 7 on the 13 PIN plug, and then matched up the innner-most pin (Ground) with Pin 6 on the big plug.
Then you need to wire up a simple switch (Single Pole Single Throw) to connect Pins 9 and 5 together. For the switch and the female headphone plug, just hit up your local radio shack and they should help you find what you need.
When you throw the switch on, it forces the head-unit into Accessory mode, and it should display ACCS.
You should now have auxiliary audio input through the new connector. YAY! I don't have to buy a new deck after all!!!