You can't - legitimately. Thats how the motor trade claws back your cash having been beaten to the floor on the original retail price for the car. I'm in the same situation, best get friendly with your local VW/Audi/SEAT privateer and see if he'll let you borrow the AUTODATA DVDs which they all use now. SEAT may sell you one, they are several hundred quid, plus once you find out what needs to be done you'll probably need special tools to do it, which only the workshops have. Oh, and don't forget all the electronic diagnostic stuff which will leave you going round in circles. Take it to the privateer who set up on his own having got fed up with working for the big boys !! - I've been there, done that.
Mike
June 2008