How to allow Split screen on black ops PC

Hi all is my first new thread. Im sorry if i make any mistakes.
Im interested how to make split screen on black ops. I have 1 xbox controler mouse and keyboard. i thoughts is it possible for one preson to use xbox controler and other keyboard and mouse.

I hope some one will help me because i need it. I tried to go options> controls.
At the bottom said GAMEPAD I allowed it but then keyboard was disabled. im think is it something in confi file. i Found interesting line in there:con_gameMsgWindow0SplitscreenScale "1.5". idk if that has something to do with it. Ill would be pleased from any advise i will get.