Mount Wireless receiver for audio in

My understanding is the audio input on the side of the camera takes a 2,5mm sub mini stereo jack. I want to mount my Azden wr22 pro receiver , so I can place a lav on the speaker and get solid audio reception, the receiver will not make metal contact with the hot shoe nor would it need power from the hot shoe. I want then to plug a 1/8 mini jack into the receiver and then plug the other end into the camera's audio slot. I assume I will have to buy an adapter 1/8 mini into 2.5 mm sub mini. Will the camera receive the audio signal eventhough I am not making electrical contact with the hotshoe?

Separate question.... I see in the menu, Histogram, but it is grayed out and will not open. Do I need an upgrade to get this to function?

Any help will be appreciated.

Thanks ,

Ralph Bowman