I'm working on the same problem. My first thoughts are to make a "dummy" set of contours, set to a dashed line type. When placed under the ArchiTerra countours that I am modifying they represent the change just fine. If Fabrizo is reading, maybe this could be worked into the next release? As far as hatching my cut and fill, I haven't gotten to that point yet, but I may need to take care of this in a similar fashion. Let me know what you end up doing, just for reference... anyone else?
+pablo