Hey there! .uax-files are used in UnrealEngine 1, in games like Deus Ex 1, Unreal 1 or so :) If you just want to extract it's contents you could use Dragon Unpacker . The UDK is powered by the Unreal Engine 3, which is not using the .uax-fileformat anymore. ;) I don't know if it does work standalone...

Woow awesome what you achieved so far, cra0 :) I didn't expect anybody to get onto the files of this game that quick :O So did you write an extractor for these files yourself or is there already a program out there which can open these archives? I would really love to take a look at the Models espec...