Trailer light DIN plug at tractor

[rctrucker2]

I am building a Freightliner Cascadia. The trailer lights DIN plug is supposed to be attached in the bottom left corner of the sleeper roof. I have seen trucks on this site where the DIN plug is mounted between the frame rails and not on the body of the truck. However most of those trucks were stretched. My truck has the standard frame with the optional Tamiya aluminum fifth wheel servo mount. Due to the frame cross member mounted at the point between the end of the servo mount and floor pan of the cab, a raised box of some sort would be needed to hold the DIN plug if mounted on the frame rails. Does anyone make a part that would allow me to mount the DIN plug on the frame rails and not the cab of the truck? Anyone have any ideas on how to do this. I do not have the skills to build something from scratch so any help on this would be most appreciated. Thanks.