From what I can tell, I think what you're describing is exactly what Creator actually does! To add a new support structure, just click on the build table at the location where you want the support pillar to extrude upwards. Personally, I usually have to play with the view a bit to find an angle where I can easily add these structures. Many times, what is actually directly below a feature of my model does not appear that way from the view I have chosen. But I assure you, that's what it's doing. What might be good to add is a visualization for support pillars that don't contact the model just so you know where you mouse is currently generating the tower. Right now, it only shows you the pillar if it actually contacts the model.
And chuck, I completely agree! We usually let Creator automatically add support structures based on an overhang angle ~45 degrees and then just make minor modifications using the Add/Remove tools. Looks like you already figured that out
