Problem with null vga driver in NT Embedded

I have a Winsystems PPM-TX PC/104-plus embedded PC that we have been
developing on for about 8 months with no issues - For development we have
had a video card installed but for the final system it is intended to be
headless. Today I built a kernel with the null vga driver and null
keyboard/mouse driver. The problem is that the system won't boot up unless
the actual video card is plugged in - the null drivers appear to work OK in
this case with the card removed the system never boots. There are no
entrries in the event log so I don't think the OS is even starting. On the
surface this would appear to be a problem with the PPM-TX, however I am
pretty sure its intended to run headless (there is NOT an option in the bios
to turn off the video though) There are a couple of other cards which give
indications that the bios is at least making it through the post (I can see
the lights on the scsi card searching for drives - which doesn't happen
until just before the nt loader usually appears). Any thoughts on this and
how I might figure this out ?

I am SO confused...

Chris

turns out the problem was NOT the Winsystems PPM-TX hardware hanging up - I
obtained modified copies of the NTLDR and NTDETECT files which replace the
standard ones in the project and now the unit will boot with the null vga
driver and no video card installed.