Rust Warranty

[enaknosaj]

Hello everyone!

Has anybody made a claim for rust on an Audi here? If so I'd very much like to learn from you!
We bought an Audi (through my company and I liked it so much I kept it on as a personal vehicle) - its an A4 Avant (Dec 1996). The tailgate now has a couple of little bubbly bits in the paintwork. This isn't too surprising since the tailgate is I suppose the bit of the car that gets the most dirty etc. One bubbly patch is in the middle and one adjacent to the glass.
I'm wondering whether its as easy as dropping into an Audi garage and saying "isn't this thing meant to be guaranteed against rust for 10 years" or whether there is a whole load of beaurocratic reasons why they get out of it?
Oh, the car is otherwise lovely by the way - 206,000 miles :-)
Other things you might ask me... We bought it from new from an Audi dealership, its been regularly serviced (not that that would affect rust I would think) - although a couple of the stamps are VW rather than Audi (the dealerships went awol :-) which I hope isn't too great a problem. Also although the front wing has been replaced following an accident - but the tailgate hasn't been touched or affected by anything - i.e. is original.
Any experiences or advise would be greatly appreciated.

Many thanks

Jason.