I know this thread is kinda old but.. Meh, this is on topic. I am reasonably disappointed about all the threads where someone asks about using PS/2 devices and then provide/receive no real information so I will post plenty in the hopes that it will encourage others to make more detailed posts.
Does this work for everyone else to allow them to get USB Mouse and PS2 Kb to live together?
It works for me. All I did was edit the previously specified version number then drop it into kext helper and rebooted.
My keyboard is an old Focus Electronic co. EZ Key that I got with a second hand Pentium I system a while back. I wanted to use it because my only USB keyboards are those short original Apple USB Keyboards. I was using the older Apple ones with my previous G3 and G4 mobos but they are mushy after so many years of being used basically every day and unless I am mistaken I can't access my current mobo's BIOS with them. It helps to have a full compliment of keys for other things anyway.
If this had not worked I would have stuck it out with my Apple 'board until I picked up a Razer Lycosa. Now the money that would have been spent on that can go towards a Logitech G25 wheel.
My mouse is an "el cheapo" Logitech M-UV96.
Continuing on, my system:
Celeron E1200 3.2Ghz w/ 400Mhz FSB (AC Freezer 7 Pro), Asus P5K(vanilla)
|x2| 1GB OCZ Platinum XTC Rev 2 DDR2-1000 5-5-5 15
|x2| 500GB 7200.11 'Cuda SATA/250GB 7200.10 'Cuda PATA, Pioneer DVR-112D PATA
Radeon HD 3850 256MB (715Mhz|1035Mhz), 17" Dell D1028L @ 1280x1024
Antec Neopower 650 Blue, Generic(?) ATX fulltower case (6x 5.25"/5x 3.5")
Sansui G-4700 receiver +2x 60w spks/Yamaha YST-M7
OS and such installed in roughly this order:
Kalyway 10.5.1 DVD -> Kalyway 10.5.2 combo update -> AttansicL1/Natit+menufix/PC_EFI v8/recent netkas SMBIOS/Time Machine update.
The ALC883 install option that came on the install DVD for certain Gigabyte boards worked without issue.
I originally was using v1.0.3 of AppleACPIPlatform.kext but when I installed ACPIPS2Nub.kext I decided to up to version 1.2.1 of AppleACPIPlatform.kext. This worked fine aside from System Profiler being on crack and calling my system a "Mac" and "P5K" with some other apps calling it a "MacBookAir1,1". (That is an amazingly huge, horrible and dirty insult and I simply cannot live with it.)
Normally my System is a "Asus P5K" "MacPro3,1" with apps reporting that. Anyway, so I tried v1.0.3 of AppleACPIPlatform.kext and System Profiler returned to normal but the PS/2 keyboard did not work. As it turns out version 1.1.0 of AppleACPIPlatform.kext works just fine (or so it seems) without System Profiler and other apps reporting odd things.
Ok, so it was not System Profiler's fault but it is still more amusing to say that it was on crack due to not having the correct information. I suppose that is akin to shooting the messenger... *shrug*