Dave I don't have an M5 to look at. There should be an empty keyed servo connector slot with the cover removed.
I just followed Gary's instructions and it works like a charm. The one note I would like to point out is that when you first plug the receiver into the S bus port you only see a very fast and quick bleep of a power light. It's only when you start binding and finishing binding do you see the orange power light on the receiver. Also I found it a little odd that Spektrum servo cables with the little extra notch on them won't plug directly into the receiver. I had cut the little tab off it for it to fit in the servo ports. I ended up using a servo extension cable to mount it like I have below as it was just a tad too short. Here's some pictures of the M5 opened up and how I mounted the receiver.