I removed the "chin" under the stereo. It pops right off, but don't yank b/c you have to unscrew and remove the lamp. There isn't enough room in front for the switch, but there's plenty of room the farther back (well, towards the front of the car) you go. I don't remember if we dremeled from the outside in or the inside out. Try to find some spare plastic of similar thickness and watch how it flares as you drill. It came out absolutely beautiful.
Do some more searching and you'll find a link to the "headunit removal" site. You will need to remove the entire head unit from the dash to get back there.
Also, be careful when you cut the wires behind your nav screen, they are small, but the wires you have to splice them with are absolutely TINY. I'm talking 22 gauge splicing to 28 gauge.