does ColorSpaceSuite ConvertToMonitorRGB work at all ?

Hi,

I'm trying to use ConvertToMonitorRGB to convert from the image profile space to
the monitor color space, in the same way that photoshop display it.
From what I understand from the doc, it seems the good function to do it.

However the following piece of code :

      Color8 src; src [0] = 0;
      src [1] = r;
      src [2] = g;
      src [3] = b;






      Color8 dst; SPErr err = _color_space_suite.ConvertToMonitorRGB (
      	plugIncolorServicesRGBSpace,
      	&src,
      	&dst,
      	1
      );





will return 'Parm' for err.
It will return 'Parm' also if I replace 1 by 3 or 4 in the function call. (the
actual color number seemed more logical to me, whereas the documentation seems
to account for all channels)

I've been trying with CS3 on Mac if that matters, but do someone see where is my
error ?

Thanks for any advice on that issue,