I've done it. Just pop that nice plastic piece off that's behind the armrest and there is another plastic piece (which is the back of the seat) just as that other guy's picture shows. I cut through it with a sander disk on a dremmel. Very easy, it just makes a LOT of dust. I did it for my subwoofer though, so I also ended up cutting the first plastic piece too. Unfortunately I couldn't find pics of what it looked like while in progress, but here's a couple of the after...
Good luck and happy Thanksgiving!