If you upload the fzpz file of your part here (upload is 7th button from the left in the reply tool bar) we can help you out. That said, its fairly easy, in Inkscape in the copper1 group create a circle with the diameter of the hole and a stroke-width of 0. That will create a hole in the board with no copper surround. You need to name the pad (change the id) to nonconn0, nonconn1 etc so Fritzing knows you want a hole there. I think this still works on smd parts but I don’t know that I have tried it. To test export the grebers and check it specifies a hole there.
Peter