Updated as of 2/01/10
after bumping around the forms for a while I found how to make sure Ren x runs on steam
obviously you want to download Ren X 0.5 but if you want to download 0.35 you can.
1. Extract the Renegade-X 0.35 or 0.5 installer from the .rar file onto your Desktop.
2. Install Renegade-X to C:\Users\YOURUSERNAMEHERE\Documents\My Games\Unreal Tournament 3\Renegade
*note* you do not have to make a shortcut if you use version 0.5
3. Open the Unreal Tournament 3 program folder and find UT3.exe (C:\Program Files (x86)\Steam\steamapps\common\unreal tournament 3\Binaries)
4. Make a short cut of UT3.exe
5. Right click the short cut and click properties then add "Target" box enter the following: " -mod=..\Renegade -solomod" right after the quotation marks *make sure there is a space between the quotation at the end and the dash.
6. move it to your desktop
7. open steam and click my game tab and right click on UT3 and click properties at the end
8. then click on the button that says set launch properties, and type in -applaunch 13210 -mod=..\Renegade -solomod
that should fix everything