BMP 2 colours black/white problem

I want to create a 2 colours black/white BMP in Monochrome MS Windows .BMP file format (ghostscript output format "bmpmono").

If I tell PDFCreator to create 2 colours (Black/White) BMP, it gives output format "bmpsep1" to ghostscript (Separated 1-bit CMYK .BMP file format, primarily for testing).

How can I tell PDFCreator to give ghostscript the output format "bmpmono"?