Fuel Mixture Screw Stripped

Hey guys, so I took apart my carb to clean it and low and behold a gasket was completely dissolved inside so I rebuilt the entire thing. The only problem is, it still doesn't start. I have tested for compression and yes, it's got lots of that. And it also has a good spark when I tested it. Lastly, yes I smell lots of fuel from the exhaust side. So what's wrong? Well, for the first time when taking apart the carb I saw that the fuel mixture screw was stripped. Meaning I can't tighten or loosen it any because some idiot who had the bike before me stripped where the nice screwdriver is supposed to grab on the head of the screw. So my question is, how the hell do you replace the d**n thing? I don't think it will unscrew because there is a brass ring above it that looks like it's preventing it from coming out. Any ideas? Thanks.