16 Color BitMap

Hello,

        I have faced a problem that I want to save a 16-colors BMP file
as another Application cannot recognize a 256-colors BMP correctly.
However, the Delphi's SaveToFile() Function cannot be specified the no.
of bits per pixel and I don't want to use GDI to write the code also
don't want to lower the no.of colors available in the window. Would
anyone has some idea on it to do that simply ?

Thank you very much.

Paul