Mine says CX-5 too, it works except the knob and the buttons around it, and the external mic, but it must be something with the wires, i'll take back the hi-fi guy.
for the mic, did you connect the external mic supplied with the unit? I believe it must be properly connected to make calls. I could be wrong, but I ran my external mic up the a pillar and stuck it in the same location as the stock mic. Stock mic is just a molex connector held in with glue, it is easy to remove.
As for the knob, I explained how I got it to work on my car in an old post. I recommend you get your hi-fi guy to do it. Having those buttons is a nice convenience.