how to connect CD changer port to aux input

[evoldman]

Hello, Please need help!
I have GPS navigator Iway 500c. I'm going to connect it to my car radio. I have Nissan Maxima 2000. It has CD changer port. I don't use it. I don't want to use CD changer converters to auxiliary input sold by various retailers because they are 1. expensive 2. have too many features I will never use and etc.
My CD changer port has 12 pins. Actually I don't know the harness diagram but I'm going to play with pins to find which related to audio. I'll connect GPS female audio output to aux input and then will try to find which of CD changer port's pins work. Please tell me if it should work that way. Again I wouldn't like to use standard CD changer converters with iPod interface..
Thanks,
Eliya