Microsoft Wireless Keyboard & Mouse

I'm currently using the Microsoft Wireless Natural Multimedia Keyboard and the wireless Intellimouse Explorer. I enjoy using the mouse but for some reason the keyboard's function keys do not function. I've used the included software to map the keys allowing for the function keys to be "handled by Mac OS" as it states in the system preferences. Yet whenever I try using the function keys to enable expose's features, they do not work. I'm just wondering if there are other owners of Microsoft keyboards that are having the same problem. I was using the following software that was included: Intellitype Pro 2.2(Keyboard software) and Intellipoint 4.1(Mouse software). I visited Microsoft's website and downloaded Intellitype 5.0 and Intellipoint 5.0. Now it seems having Intellitype 5.0 installed, any keys above the numerical keys no longer function (i.e. Volume Control, Media, etc.)
I'm guessing these ill effects are from using a Microsoft keyboard meant for a PC platform with a Macintosh.