I've tried hooking up my Sirius Sportster any way I can and the 700BT won't recognize it. I've used the aux in on the front panel and even tried another adapter I have that works through the IP-BUS connector. Neither one works. Is there no true audio only aux input on this thing? I really don't want to have to spend another $100+ on external Sirius tuners. I also like having the pause and rewind features on the Sportser.
The one on the front(AV2) should work, or get the cable that has RCA outputs and run it into the back(AV1)
dont use the front input it will look like shit with the wires everywhere.
if you are going to use the sirius replay unit eithet the ip bus cable or the audio in via the back rca's will work. just change the source from ipod to video or audio in the menu. if all else fails get a fm modulator and run your sirius that way.
Do you have an iPod connected? You need to enable either of the AV inputs in the AV settings screen before they will work.
I tried the front input and enabled it yet there was no sound from it. Like black said it looks like such crap with a big white wire sticking out the front I don't want to use it anyway. I guess I missed the RCA inputs on the back. I only saw the outs for the speakers and subs, inputs for rear camera, etc. If there are audio RCA inputs back there I'll just pick up a cheap 3.5mm to RCA adapter and run it like that. I can handle $1.98. 
The front panel input is an A/V 1/8" and requires a different plug than the one you would find on a standard 1/8" stereo cable.
The rear inputs are A/V, not just audio, so there will be a red, white and yellow connector. Just don't connect the yellow one.