Gentoo on Acer Aspire 3502WLCi with bugged DSDT (Phoenix BIOS)

[Fabio <fabio.venturi@studenti.unipr.it>]

Greetings to anyone in the ML,
I got the laptop in object with a bugged DSDT (REALLY?!?!?!  :o)
So I downloaded a fixed DSDT from the acpi site and compiled it with
the iasl compiler.
Then I patched the kernel (2.6.15) so now it can read a custom DSDT
and I put the new DSDT.aml in /boot

I read on a gentoo forum that i can pass the file to the kernel 
like a initrd image, so i modified my grub like this:

[...]
title Gentoo GNU/Linux (Fixed DSDT)
kernel (hd0,2)/boot/bzImage-2.6.15 root=/dev/hda3
initrd=(hd0,2)/boot/DSDT.aml
[...]

but on restart i find:
fabio@bluestar ~ $ dmesg |grep -i dsdt
ACPI: DSDT (v001 PTLTD     661MX 0x06040000 MSFT 0x0100000e) @
0x00000000
ACPI: Looking for DSDT in initramfs... error, file /DSDT.aml not found.
Table [DSDT](id 0006) - 485 Objects with 39 Devices 93 Methods 10
Regions

I tried to create an initrd.img with "mkinitrd initrd.img 2.6.15" and
then add the DSDT.aml to it by the initrd-add script,
but during the start-up the pc hangs with the message:
"error: Unable to mount root fs on unknown-block(3,3)"

I don't know what to do, hope someone
could help me, thank you in advance
Fabio