A8N-SLI Deluxe: poweroff OK with 1006 bios, fails with 1011 and later bioses

My Asus A8N-SLI Deluxe motherboard doesn't power off when shutting down
with a bios later than the original 1006.

I would like to use a newer bios, since they support X2 chips, for
example.

I have decompiled the 1006 dsdt and the 1011 dsdt, and somewhere there
must be a difference that causes this.

I've tried to read the acpi specification to find out where I should
start, but I'm not getting it. What parts in the dsdt have to do with
powering off the system? Where do I look?

I'll attach 1006.dsl and the diff.

Thanks,
Jurriaan
-- 
Apple I (c) Copyright 1767, Sir Isaac Newton.
Debian (Unstable) GNU/Linux 2.6.13-rc4-mm1 5505 bogomips load 0.40