What version of ID? How did you make the rounded corners?
Version 8, Mac OS X. I created a rectangle, and gave the corners a radius in Corner Effects.
That would be live corners?
I don't think you can use the Convert Point tool in this situation. You can set different corner options for each corner in the Object > Corner Effects... dialog, or use the Selection tool and hold down the Shift key while dragging one of the yellow diamonds at a corner to adjust them individually.
Ah...this is different (to me) from the previous version in which I tried doing this...much nicer. thank you for pointing it out!