I'm not certain which function(s) you are referring to. For me, F9 and F10 work for Expose´ while 'fn' + F9 & F10 are for keyboard backlight brightness.
Well for the backlight function I don't believe it can be changed. For Expose´however you need simply to go into System Preferences. There you'll see the control for Dashboard & Expose´. From there you can change the function keys for Expose´ if you want.
you can switch it so that you have to press fn+Fkeys to control hardware functions. go to system preferences->keyboard and mouse->keyboard, then check the "Use the F1-F12 keys to control software features" box.
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F9 and F10 only work with fn pressed
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