Restrict CColorDialog = ChooseColor() to 16-bit colors?

[Chris Shearer Cooper]

When I open a CColorDialog (which is just a wrapper for the ChooseColor
() function) on a machine that is set to 16-bit color depth, it still
lets the user select colors that can't be accurately represented in 16
bits. For example, they can select RGB(237, 243, 237) which, when
actually displayed, shows up as RGB(240, 240, 240).

Is there any way to restrict/modify this dialog so that it only allows
users to select 16-bit colors? I don't want it to be during the
verification stage, that's ugly (e.g. popping up a message box that
says "don't pick that color", or modifying the user's selection
without telling them).

Thanks,
Chris