Ok - I just ran thought this as part of rolling back my BIOS then updating back to the latest version.
If you have an older BIOS on Win 7, you'll need to make sure you have the ACPI drivers loaded and working. If you are running Windows 7, load the ACPI driver listed for the 1005ha for Windows XP and be sure to set AsusSetup.exe to run in WinXP Service Pack 2 Compatibility.
After installing that, reboot and verify that your ACPI keys are working (FN + Function keys) for the various features. Test using the Wifi button - if that works you are good.
Then make sure you have Asus Update installed. This should be the version for Windows 7 from the 1005HA download page.
Then download and unzip the BIOS file you want to load (I used 1102).
Reboot again to make sure you have a fresh boot.
Finally, run Asus Update, and select "Update Bios from File" and browse to the 1102 ROM file that you unzipped just before the reboot.
Make sure you are plugged into the AC adapter before rebooting.
It should prompt you to reboot to install the new BIOS and you should see the BIOS loader.
After the loader is done it will tell you when to power off the machine - DO NOT power off until it tells you to do so.
When you reboot you'll get errors about the ACPI software. Uninstall the ACPI then reboot.
After reboot, install the new Hotkey software. Reboot.
Your FN hotkeys should work now. You'll also want to install the new Super Hybrid Engine v. 2.09 which is designed to work with the new Hotkey utility and Windows 7.
That's what worked for me.