Here is where I placed my Hoppy 46255:
Sorry, I don't have a picture of it mounted. I simply stuck it there with Velcro. It sits below the seat and is in a perfect position to tap the wires running between the connection under the right side cover and the rear of the bike.
I simply run the four flat out from under the seat and run it along the left side. It is zip-tied loosely to the trailer hitch (to keep it off of the exhaust). Never had a problem with that setup - 3 years and 12,000 miles of trailer pulling.
As far as the AP2... I have an Interstate, so I mounted mine up in the right fairing area... by the looks of your avatar, you have a Standard/Tourer... so no luck there. If I were you, I would cut out the divider between the battery and the little storage area for the tool pouch and owner's manual. I put an after market CB there with plenty of room to spare, so the AP2 should fit there no problem. Just velcro that to side of the battery box and you are set.
I am doing exactly that to my wife's Standard trike in the next week or two.
