There are some limitations but also .. a work around;
Select the building, go into edit building, menu. Select your piece(s) .. use copy, again from the menu. (try ctrl-D if you like, but not sure) Hit .. Done. You've got them, place anywhere.
They will add to another building but bring their own grid with them (and advatnced moved tool drops them) so you have to line them by eye and drop them freehand at the moment which is a bit tricky imo. Submitted as a bug report earlier (feel free to bump once you've tried it) though more of a desirable feature (I think, to have advanced move made available, at least) than actual bug.