I think that this is correct, if u replaced the ntoskrnl.exe with a different one to change the boot screen, SP2 doesnt "really" use this file for this purpose anymore. It may use it to some extent but not like it did before SP2, thats why SP2 no longer displays the version (Home or Pro) that you are using, u may want to try to do it without replacing any of the system files until the system actually installs.