Thunder HEsl S2567 ACPI problem

I'm trying to install Windows XP Pro on a Tyan Thunder S2567 dual-P3 board
using the Serverworks HE-SL chipset and I cant get ACPI to work.

When I install XP with ACPI on and Plug-n-Play-OS on I cant get the
integrated serial, parallel and Ethernet interfaces to work. I get loads of
resource conflicts between them and even with manual resource assignments in
the device manager I dont get them all to work.

I contacted Tyan support and their answer was: "The Serverworks Chipset does
not like ACPI. Disable the ACPI in the bios and attempt to install your
system again."

Is that Chipset / BIOS really that buggy ??
I did upgrade to the latest BIOS 1.05a, which is from 2001 so it isnt very
likely that Tyan will release a new one.

Unfortunately when I install XP with ACPI turned off I loose the
functionality that after shutdown it also powers off.
Any workaround for that ?

thanks
any help appreciated