[smileynialley]

if you look in the technical section i posted a thread about how to connect headrest monitors to an aftermarket headunit. The principle is still the same weather the monitors are hummer ones(vizualogic) or aftermarket, the connections will just be slightly different.
You will have a live feed, negative feed and at least 2 connections for the av input.

My headunit was already installed but having looked at the back of it, it appaears that it is just a simple connector adaptor from hummers wiring to the headunit.
I havent managed to wire in the steering wheel controls yet but there is an option for it. Most headunits will have a few wires at the back of them for steering or remote controls. Apparently u cant just wire directly from the steering controls to the headunit, you need another connector.
Hope this helps in some way.