L4D: way to do Splitscreen without Xbox360 gamepad?

I've seen the trick that you can do on L4D for PC to do Splitscreen, however, it seems it requires the official Xbox 360 gamepad to do so.

Come on, is there a way to do it without the Xbox 360 gamepad? like, i can use my two Logitech PS2 gamepad clones while using Xpadder to play splitscreen?

Come on stupid developers, can't you just make a seperate control list for two players in the first place, like, two keyboards and two mice? i mean, duh!