Well, most of the members from the developers team got their hands on a copy of UT3, so did I.

Unfortunately, it seems UT3 works slightly different than RoboBlitz, more in the way of making a Total Conversion of it. I am eagerly looking for a solution.

Though, I already managed to get UT3 to run some custom content (and I do not mean a mutator) but it isn’t what I want. It seems that for now, we have to edit the main configuration files (the INI’s that can be found somewhere in My Documents) to get UT3 to run what we want. This isn’t the cleanest way to do it unfortunately.

As long as Epic won’t release some proper documentation about command-line arguments and such, I’m afraid you will have to make a second copy of UT3 on your hard-disk (a stripped down version that is). This perhaps raises an discussion: “Would you make a second copy of UT3 on your hard-disk, just so you can play both UT3 and Project Stealth?”

Edit: Perhaps there is some hope… I just found this in the one of the core INI files:
“ScriptPaths=..\%GAME%Game\Script
FRScriptPaths=..\%GAME%Game\ScriptFinalRelease
CutdownPaths=..\%GAME%Game\CutdownPackages
CutdownPaths=..\%GAME%Game\Script
ScreenShotPath=..\%GAME%Game\ScreenShots”

Do you see the %GAME% and Game? Well ut3.exe in this case, makes %GAME% UT, which makes it start up UTGame which can be found in the My Documents folder and in the Main installation folder.