You can plot dashed freehand lines from ClarisÊCAD with MacPlot Professional. What you do is this:
1. Color all the lines and shapes that ClarisÊCAD can't dash on its own with the same color (i.e. green).
2. Use MacPlot Pro to create a parameter file that will dash all green lines.
3. Plot
For more information, consult the MacPlot Professional manual.