1.First u must download these patches:
|Left 4 Dead 2 Master Update Version 2.0.1.6
-Left 4 dead 2 miniupdate 2.0.1.6 to 2.0.1.9
|Standalone Patch-T10.5 R1
2.For changing name open the styder.ini file(you can find it in game directory folder).
3.Now it's done! you just need to open the game and press ~ bottun to open the console then write connect and game server IP
If the console is disable go to: Options==>Keyboard/Mouse==>Allow Developer Console==>Enable