2003 acura mdx audio input

I want to install an xm radio directly into the radio receiver and not use a cassette adapter.  I can use the audio portion of the audio/vidio input located in the armrest of the third row of seats, but I would prefer inputting the audio behind the radio receiver.  If I could locate the wires going to the audio/vidio input, I could, I suppose, splice the input into these wires.  Am I thinking correctly?  Does anyone know the color of these wires...where they are located?

Any help will be appreciated.