Programming CNC with Router-Cim

I have been programming with router cim for a while now for cutting wood and plastics. Typically my cuts are either an outside cut, a centred cut, or an inside cut. I had a friend ask me to make him some plastic signs for advertising his business with his company name etc. I can't for the life of me figure out how to program a cut for lettering that would have a hole in the middle (ex Capital B). I thought maybe subtracting the solid in autocad, but that didn't seem to work. Anyone know what I need to do to program that cut correctly?