Unable to change printer options on Windows NT4.0

I am currently trying to set the orientation and paper bin of a printer using
DocumentProperties().

I'm able to do this successfully, as I then create a printer device context
and send text to the printer using TabbedTextOut(). This works OK.

However, I also need to send a Postscript file to the printer and select the
A3 paper bin.
For this I'm setting the printer options using DocumentProperties() and then
using
OpenPrinter()....
WritePrinter()...
ClosePrinter()...

to send the data to the printer. However, the output appears on the A4 paper.
If I use TabbedTextOut(), I get the PostScript text file printed on A3 paper.

So, does anybody know how to update the printer setting so that I can print
the postscript file correctly on the A3 (non-default) paper.

Any help much appreciated.

Thanks,
Mark.