U have made this nLited. If I m not wrong there is a $OEM$ having CMDLINES.TXT file on the root of XPCD.
If it doesn't exist make this one and add
OEMPreinstall=Yes in Ur WINNT.SIF.
save Ur reg file with .reg extension and copy them into $OEM$ folder and add these lines
CMDLINES.TXT
CODE
[COMMANDS]
regedit /s <file-name>.reg