This is a GREAT mod Black, and your pictures and directions are very nice! I had an idea inspired by Chief's comment about the tierd loading thing that I thought you could comment on having been in there already.
If you drill the hole for the outlet high enough to be above the "tierd loading" 2x4 location and at the aft of the 3-1/2" slot that it sets in (instead of the front end), would the hole still go into the storage box? I'm hoping that it won't actually as I've seen pictures somewhere of people with their storage boxes completely removed and I'm betting that would give you a lot of access to work behind that area.
If that works, I'm thinking it should allow the outlet to be mounted with the supplied screw-on nut instead of tape as well as keep the wires out of the storage bin (though you'd have to route the wires differently). Heck, if you take the storage box out I bet you could put the screw-on nut on the back of your install too.
Hopefully the back edge of the tierd loading slot offers as much protection as the front edge. Looks like it's a little shorter there but hopefully still as tall as the plug sticks out. I doctored up a couple of your pictures to show the mounting position I was trying to describe.
What do ya think?
Re-shrunk to 490 pixels and redid FTP. Hopefully this image fits a little nicer. Sorry for the fat-finger on the previous post. -TXAVy