Hi, I've the same problem with my R/T that I have bought one week ago.
I can tell you that I'm Italian, so I have an european version (I don't know if there are differences with US version), I've Entertainment Group I, MyGig, Uconnect and navi.
When I asked to my dealer why there wasn't the cable, he told me that with the navi factory equipped the cable is not supported, but I'm not convinced about this answer.
Now I'm waiting for a more specific answer from him, he is asking to Dodge Italy.
Bye, sergio