I've been looking to enable the trailer hitch zoom without VO coding for the trailer hitch. This way when I install a hitch I'll have that capability no matter what hitch I install. Well it was easy. I'm not sure if the coding is the same with a newer NBT but on the CIC it was simple. To do this Edit the following FDL under your CIC (once in the FDL i found it easy just to search for the word "macro")
MACRO_TRAILER_COUPLING and change from nicht_aktiv to aktiv
That was it. You will then see another selection in your Rear Camera (at the bottom) that looks like a trailer hitch and have the zoom.
There are also some other interesting macro functions (rear_view and side_view). I haven't tried those yet.