MacDraw Pro will not plot gradient fills with either MacPlot 1.2 or MacPlot Professional.
This behavior was implemented for the following reasons:
1. It's impossible to get a smooth blend since the plotter only supports seven colors.
2. Plotting gradients could be very time consuming and would wear out your pens.
3. MacDraw Pro implements Region Clipping when printing gradients and none of today's plotter drivers support this. In fact, MacDraw Pro is unable to recognize when you are printing with PLOTTERgeist and will end up plotting gradient fills beyond an object's boundaries because it is unable to clip it.