It seems that with SP3 that it is no longer a requirement to enter a key or to do activation and that these can be done after installation is completed.
Per SP3 notes:
So, 2 questions.New features in Service Pack 3:
Installing without requiring a product key during setup for retail and OEM versions
Slipstreamed retail and OEM versions of Windows XP with SP3 can be installed and run with full functionality for 30 days without
a product key, after which time the user will be prompted to enter a valid key and activate the installation. Volume license key
(VLK) versions still require entering a product key before beginning installation
1. How do I create an unattended so that it bypasses asking for the key and activation. Do I just enter in a temp bogus key or is there some winnt.sif setting to skip this and activation?
2. Can this be done with a SP2 that has been slipstream to SP3 or does the key and activation bypass require a new SP3 OEM or retail CD?