I done this retro fit on my 06 GTI, luckily for me, I only had to change the stalk and code it in! already had the right modules and the wire etc.. I think they are pre fitted 06 upwards - indeed I was lucky, as I really wouldn't of wanted to run that wire if I had to, looks a right pain! but then sometimes things look harder than they actually are.
reading your first 2 posts, I was thinking.. coding.. got to your last post and was happy to see you solved it with coding :)