Hi,

maybe:
hxxp://support.microsoft.com/default.aspx?scid=kb;en-us;293765&Product=winxp

>>RESOLUTION
>>Depending on your needs, there are two ways to prevent Setup from being >>halted with this warning message:
>>• Set DriverSigningPolicy to ignore in Unattend.txt.
>>This entry causes unsigned installs to silently succeed.
>>• Set UnattendMode to fullunattended in Unattend.txt.
>>This entry causes unsigned installs to silently fail, unless DriverSigningPolicy is >>set to ignore in the Unattend.txt file.