I have a DDX917WS and also ordered the pre-made harness from Carbon.
Can confirm my camera NEVER worked with their harness. A local shop I took it to told me that it didn't include the 12v/6v drop (Carbon assured me this was fine and wasn't the problem), and that it wasn't wired correctly to take a camera signal. Unfortunately I don't know how they modified the harness or if they had additional harnesses... I just wanted it fixed and they delivered.
A couple other people here have used the carbon harness mostly without issue (amp trigger was not wired on early revisions) with USA cars.
I do have a Canadian car so maybe there are some minor wiring differences?
If I had to do it again I would either learn to make my own harness or let a local shop build one for me. Carbon doesn't have bad customer service but there is no way for them to effectively troubleshoot this overseas. Probably why they don't ship these units over here anymore.