XP SP3 Installation Problem

[MOONLIGHT SONATA]

Y'day i've to prepare an unattended XP SP3 Cd. After setup finished, to my disbelief i find that my integrated Optional Components add-ons failed to install. Even original portion of SP3 sysoc.inf failed.

I looked into my add-on INFs and CABs - find no trace of any error there. In [DefaultInstall] all install perfectly. I then integrated the same set INFs and CABs into old XP SP2 disk and everything installed without fuss. I don't use neither RVM Integrator nor nLite. I always prefer to build by hand.

Here comes the question - does Microsoft put any signing verification for SYSOC.INF in SP3? I don't modify SYSSETUP.INF, so never patched SYSSETUP.DLL. Only SFC_OS.DLL is patched in my source.

Is there any DLL file needs to be patched so that additional sysoc.inf entries could be integrated?

Any help would be appreciated, since installation right now is as good as hitting F3 to quit.

Regards.

MOONLIGHT SONATA