Using VWCDPIC & CD controls with iRiver H300?

[brihall]

I have an iRiver H320 with KOSH rb-2.9.8 installed, and a 2003 VW TDI w/ Monsoon sound system & in-dash CD. I see a description of how to connect an Archos player with Rockbox to a VWCDPIC interface, my question is:

How can I connect my H320 to a VWCDPIC and control the player via the CD changer controls?

In my car, there is an amp in the trunk for the Monsoon, so I'm not sure if I can plug the VWCDPIC in back there or if I have to pull the radio out (not wanting to do that).

If this isn't possible then I suppose I just look for a iRiver remote control.