cut a slot of arbitrary shape in IE3D

I want to cut a slot of arbitrary shape on a structure of printed monopole.How Can I do this.e.g. I want to cut a circlular hole in an ellipse on the same pane.Can we create two shapes in same plane and perform cut operation.Please let me know step by step.

Please build your shape_to_have_a_slot_cut_on_it on z1. Build the shape_of_slot on z2 (an arbitrary layer). If the shape_of_slot contains multiple connected polygons, you should select them and select ADV EDIT->MERGE SELECTED POLYGONS to merge them for better result (even it is not necessary). Then, select the shape_of_slot and use ADV EDIT->BUILD HOLES AND VIAS FROM SELECTED POLYGONS to build the hole on z1. There are some settings may affect the results. Please try different ones and see how it works. By the way, such a process will be very simple on the IE3DLIBRARY V12 to be released. You just define the 1st shape as regular object and the 2nd shape as boolean object, it will do the cutting automatically.