Sorry it's been raining all day here!
These are pics of the rear bumper inserts when I had them off to CF wrap them last week though........
However it appears you have a different take on the word 'hitch' to us European guys who can spec a detachable swan neck 'towbar' PLUS increased towing capacity on our X6s. As I understand it, the hitch you are talking about is something which fits onto the chassis and is not a totally removable item like ours??
This is really weird as my car was built in the US, but obviously to UK spec!!
One other observation; the BMW Performance rear diffuser (part of the Performance bodykit) does not have this removable towbar section and just has a big cutout where it should go. Therefore there can be no harm to the towing electrics etc even if you have a slightly larger aperture cut to accommodate a hitch.
Good luck.