I'm running on a Dell Studio XPS 1640 Laptop and have found you need the
ApplePS2Controller.kext. I would suggest placing it in /System/Library/Extensions and issuing a 'touch' on the /System/Library/Extensions folder to force a rebuild of the Extensions.mkext library.

There are a few ways to do this, I didn't read all of your previous post to see your exact setup but I know you can run into a 'chicken-and-egg' situation with a non-functioning keyboard or mouse at boot-time and noway to physically copy the correct kext to it's location without an input device !

If you have any further questions, let me know and I'll see if I help post some helpful suggestions/alternatives