aux input through hyundai CD changer port

okay, here goes. i want to make a home-made aux input adapter for my hyundai factory CD deck. it's a deck with changer controller, and has an 8-pin DIN port on the back. i have obtained the pin-out info and know what each pin is for. HOWEVER, i need to know if it is a simple matter of applying either ground or voltage to any of the pins to "fool" the HU into thinking the changer is connected and therefore switch into "aux" input mode. here's what i know about the pins: pins 1,7 [L,R audio input] pin 2 [CD ON] pin 3 [BUS] pin 4 [B+] pin 5 [M. ground] pin 6 [N.C.] pin 8 [A. ground] here are my questions: is pin 5 "main ground"? is pin 8 "audio ground"? is pin 6 blank? i gather that bin 3 is the data bus and uses some sort of protocol is it possible to apply ground or voltage to pin 2 to cause the HU to think the cd changer is "on" and activate the aux inputs? i found the same deck as mine on ebay for $30. i was thinking of buying it to test this out (in case i burn it out trying, i'm only out $30. an aux input adapter, if one were avaiable, would run me $50 anyway!). is there ANY HOPE? Thanks!

fforgot to mention the obvious: no aux input adapter exists at this time for this deck. i have searched high and low.

i'm bumping this up

How did this work out?