Since the thread stays here, I'll try.
To enable Bitsetting with an 109, you'd have to crossflash it with an Buffalo firmware.
To achieve that, you need to use either DVRUpdate or DVRFlash. Both come with readme files (normally), to explain the important things. You'd require an suitable kernel and normale firmware for the update.
However, it's most important that you know what you are doing - otherwise your drive could be damaged beyond repair.
You can find info & links in the Asus/Pio subforum.