Tyan S5383 / unlock VT-x

Hi!

I'm trying to use Intel VT-x on an Tyan Tempest i5000PT S5383 board. Although there is an option for "Intel Virtualization" in the setup, the feature remains unusable ("locked") for any operating system.

I suspect a bug which causes that VT-x remains blocked.

The BIOS can be found on Tyan's FTP server: ftp://ftp.tyan.com/bios/S5383_v201.zip

Thanks for any help ;-)