boxjoint, thanks, but it's really not worth my time to get into something like this that has limited results.
The workaround is to build a 3D door handle (and a 3D door louver, and kickplate), and stick it on each of the doors in the 3D model layer (where layers are linked and the layer is used for creating Renderworks bitmaps and viewports). This stuff could more effectively be put within the door symbol in an edited 3D view, I guess, but I'm working with a tiny building with only 6 (identical) doors.
Regardless, the developers ought to make the effect usable; hence this post, in this Wishlist forum.