Is it stripped in the hub or is the stud itself stripped?
If the stud itself is stripped, those are not pressed in studs. There's a socket head on the end of each of them, in which will fit the appropriate sized allen wrench. If it doesn't back right out, you'll need to apply some heat. Lots and lots of VW places sell the studs.
If it's stripped in the hub, you have two choices, both of which involve removing the caliper and then the hub. We can get into that once we know what you're talking about.