The CD changer doesn't pull a pin to ground or anything that easy or we'd all have iPod adapters already. While the actual inputs are analog, it's a serial connection sending over commands to the headunit that make everything happen and it needs to see this for the inputs to be live. There are only two ways to make this work, Figure out how to get another similar radios software on there that lets you use the aux in or actually figure out what the commands are that the CD changer sends to the and make an interface that talks between the iPod and the radio.