Hi Luka,
as CRM32Pro is based on SDL 1.2.x and it does not support more than one monitor... I have to tell you that is not possible to render to 2 monitors.
The only one could be if your video card emulates a big screen resolution using both monitors, so in that way it will be transparent to any other application.
Cheers!
P.S.: SDL 1.3 (or 2.0) will support it, but is still in development.