ways to make a drill hole on my design using hfss

Hi there. I am designing a circuit board using HFSS (since I don't know how to use AutoCAD, I am going to design with hfss and export the file into DXF format).

On this design, I need to make some through drills that can connect the top and the bottom. (in that way, top layer can be connected with the bottom layer)

So it is basically a hole with copper on the outside. If I use HFSS subtract operation, I can only make it either a vacuum cylinder or a copper cylinder.

Is there a way to make it copper only on the outside and air inside?

there are two way:
1) in the vacuum cilinder asign PEC to the internal
surface
2) make another smaller cilinder on the copper one and
substrated it.