using Sysrep - after reboot it needs serial #? how to remove

[scorpiots]

hi everyone. I'm learning NT admins stuff. I have run sysrep to simulate cloning multiple machines. but on the next reboot, it asks for windows 2000 serial #. is there a way to put this in answer file?
I have tried setupmgr.exe but its not in any settings there.

thanks for everyone's help!