Disable brightness keys on iMac

I know there used to be an option in display preferences but I cannot find it anymore. One option that is less preferable is under keyboard select "use all F1, F2, etc. Keys as standard function keys" that will make f2 be just f2 and if you want brighten the screen you'll have to hold the Fn button. The downside is if you use the Exposé/Launchpad/iTunes play buttons you'll have to hold the Fn button to hit them.

Also by default under keyboard shortcuts f14 and f15 are also set to brightness (I don't get why they have two keys dedicated to this) but you can disable that under System Preferences -> Keyboard -> Keyboard Shortcuts -> Display

Maybe someone else knows how to just kill the brightness buttons in Mountain Lion...

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\~K