There is no way to get your fingers up there. Looks like the amplifier is right up against the bracket.
Let's just clarify here for others. It sounds like you are trying to take you license plate or license bracket off...not the rear reflector under the turn signals. I assume that if there's an amp back in the way, you must have a SEUC??? Your profile doesn't tell what bike you have, which can make answering questions a bit difficult. I know that I got a chrome license frame, and took one look back there, and since my bike was in the shop at the time, I just told them to throw that on too. Which means, I'm not much help, since I saw how tight it was and went the chicken chit route and let the dealer put it on for nothing. I'll be paying attention here though, as I have a new plate coming for my bike in the next few weeks and I'll have to deal with this issue then. I did take another look at it, and it looks like you should be able to get a wrench in there. Again, I'm making an assumption on what bike you have and still no clue what year either. It does look like the 09 SEUC from the little picture on the side, but those pics are small and I've been known to guess wrong.