Radio mute cable (STiR+ install)

[takethecake]

After going without it for a few months, I'd like to make use of the "radio mute" cable that comes with the STiR+ radar detector. The problem I've been having is that the speaker is awfully quiet, so I often don't hear my alerts until it's too late (been lucky so far tho...). In theory, I should be able to wire that radio mute cable somewhere on the back of the stock BRZ head unit, but A) I can't find a pinout diagram anywhere, and B) I've never done this before, so I don't know exactly how I'll wire it in there (do I have to cut anything, etc?). The radio mute cable is just a wire - no connector on the end. Has anyone done something like this yet, or have any insight? All I was able to find was this picture of the head unit (at least I'm pretty sure this is the right one), but searching this model # didn't get me any closer: http://s49.photobucket.com/user/Sylv...2-Top.jpg.html

On a side note, if anyone has questions about the STiR+ install (or laser interceptor system - I did that too), I'd be happy to answer to the best of my ability! Other than the low volume both systems work perfectly

[takethecake]

Update - found this post that has a written pin-out of what I THINK is the BRZ head unit (at least it's got to be close): http://forums.nasioc.com/forums/show...28&postcount=9

Unfortunately, I'm not sure if any of these pin descriptions match what I'm looking for - there are a lot of acronyms I'm unfamiliar with. Maybe something on the 28-pin connector?