Virtual Printer Driver: Grayscale Printing

Hello everyone, I am developing a virtual printer driver and need to get grayscale EMF’s.
I’m wondering what is the best way to do this:

  1. Set up the GDIINFO so that grayscale spool files are generated?
    If anyone can shed some light on how to approach this, that would be great!

  2. Convert the color EMF’s to grayscale afterward (independent of the print driver)

Thanks in advanced!