replacement stereo/SWI Jack from PAC audio

[JAG-R8]

After reading the FAQ I upgraded my stereo and thought it would be a good idea to get the PAC audio thing that allows you to use your steering wheel buttons with a new alpine stereo. I maanaged to get one shipped accross from the US but when I took it to the local ICE shop they said they didn't know how to fit it as they weren't sure which wires it connected to. I have no idea myself and was wondering if anyone here had fitted one or knew anything about them....

many thanks

Jon