schau mal ob Dir das weiter hilft.
speziell der Teil:
If you are using DriverSigningPolicy = Ignore and you attempt to install a newer, unsigned copy of a driver that ships with Windows 2000, Setup will install the signed Windows 2000 driver instead of the unsigned drivers in accordance with the ranking process used by the operating system.
http://www.microsoft.com/technet/prodtechnol/Windows2000Pro/deploy/unattend/sp1ch01.mspx