Your in windows and you want to disable the brightness, volume etc keys and have it default to the F1, F2, and so keys correct?
there should be a diamond icon in your system tray that is for boot camp, you can right click on that and select "Boot Camp Control Panel" or you can also access it at:
Start > Control Panel > (Show Classic Menus) Boot Camp Control Panel
And there should be a keyboard tab for the aluminum keyboards, click on that and it should say Use fn+F keys you can uncheck that and it will default to JUST the F keys specifically.
and to adjust brightness and volume with that selected just hold the fn key and the volume to adjust the volume or brightness etc.
im not sure if i understand what youre saying, or if you understand what im saying.
you can have the keys either way you want.
All aluminum keyboards have the shortcuts (dashboard, brightness, expose, volume etc) assigned to the F keys.
In order to use the example F4 key you will need to press fn+F4 to use it (since it is dashboard function/shortcut).
To get it to where you dont need to use fn+F4 (or others for that matter you can have them back to their normal Functions by going to the bootcamp control panel in windows to change the setting to make the Function keys default and if you needed to change the volume in windows it would be fn+the volume key.
in OSX you can do the same thing in system preferences.
System Preferences > Keyboards & Mice > Click Keyboard tab and it has a check box which says Make F1, F2 etc function keys default or something etc etc.