The magic is that I don't have to scan inf files or to generate the CriticalDeviceDatabase entries.
I'm not too sure how you create the missing CDDB entries, but from what I've witnessed, it seems to be pretty quick (a few seconds perhaps).
The equivalent process in USBoot is pretty lengthy, and takes several minutes (as much as 10 minutes from the log file in this post)
Are you doing any magic ?
CDDB entries from Windows 7 for Controller Class (IDE and USB) were previously collected and modified for XP.
These CDDB entries arre added in folder makebtregistry_tweaks in files HKLM_systemdst_Add_XP.reg and HKLM_systemdst_USB_XP.reg