you will find this can open a can off worms in security so not many people will answer you, also you will find it normally is a close to heart secret what tools people use to do this.
i can say there are many tools out there genuine and not but all tools do different cars so you end up with 1 tool for a few cars unto 2004 you will find there are a few out there pretty cheap using the 16 pin only but after 2004 apart from spending big money from 16 pin most can be done from eprom
got a 2001 golf to change instruments,brought a cheap lead off ebay,it would show id but not pin,,plugged same kit in to vw sharan no pin but now abs light is on dash,but it hasnt got abs, we learn by our mistakes a1nobby
cant remember the exact coding as each car may have different functions enabled..if you have vcds it will give you a list of coding values to make up the coding index..i know john can possibly find a coding for you if you list the cluster part number and theres also a website you can go on to find it but its on the comp at work and ive forgot what its called.lol
There are many units out there from a key programmers point of view, as john points out you get what you pay for, I use Advanced Diagnostics MVP Pro, it gets most VAG pin codes, but it costs to buy and tokens to run it, you can however get units from Chinese web sites, I got one called Super VAG from Autoobd2.com for about 85 quid, 4 days delivery via dhl, it has not yet failed to read a VAG pin code and program the keys as well so in terms of cost it saves me 15 quid per AD token everytime i use it, but beware there is a lot of crap out there, so watch your step.