Connecting a PC PS/2 keyboard to Mac

I've just bought a PS/2 to USB cable to use PS/2 PC keyboard (Compaq SK-2860 and Packard Bell 6301N) in my Mac (OS X 10.8.4) because my Mac's wireless keyboard doesn't work:

…but my Mac does not identify the keyboard. I've got this window:

…but when I press the key to the right of shift nothing happens.

The cable works in Windows XP, and Linux Ubuntu well. I've seen this similar question but please note my issue is related to a specific PC keyboard. What can I do?

This are the steps I've follow to use my keyboard, I've tried so many things that I don't know which step is mandatory:

• Shut down Mac and wireless keyboard
• Plug in the keyboard with the PS/2 USB adapter
• Switch on Mac

If Mac is stuck to the first gray window try to use a different USB in my case if I use the first USB the keyboard doesn't work but if I use the fourth it works.

If the keyboard still doesn't work I've try to install PS/2 driver with the Kext Utility.

Maybe first you should remove:

/Library/Preferences/com.apple.keyboardtype.plist

At the login the keyboard should be operative so you can write the password with your PS/2 keyboard. I simply ignore the Identify keyboard window that appear after login.