Transparent Bitmap

I'm having problem in printing color Transparent Bitmap on Black & White Printer.
Only color transparent bitmap has a problem(8bit ).
I used the same logic as given in Codeguru Transparent Bitmap article. But it prints Black image on HPLASERJETN5000 printer.My color monitor displays proper Transparent Bitmap!!!!
I think some problem in conversion from color to black & white.
I need immediate help on this as it is critical.
Please suggest me some method.
Platform : WINNT 4.0, SDK
256 color bitmap which is nothing but a red RECT having one GREEN rect inside with green as transparent color.