As far as I know, there isn't a solution to that.
I too have wanted to do that in a few of my worlds, but to no avail. The best advice I could offer is the same as what Mark suggested.
However, all the a2c objects are actually zipped folders, so if you open them like a zipped folder, you can see all the subparts as individual files. So, in a perfect world, you should be able to just drag the "Saw" object into the robot's folder. However, we do not live in a perfect world, and for some reason, it's impossible to copy the files while in compressed format. Extracting them does no help, either, try it, and you'll see what I mean. Perhaps in the future it will be possible, though...
-jrr