Circle Editing Opposite Symmetry Points....

 From:  Frenchy Pilou (PILOU)
5128.2 In reply to 5128.1 
Just use the Edit Frame
Select something
Take the little Yellow corner Click and Move Release it in the other side
When the word "Mirror" appears you have the symmetry of the selection

If you click before on the little Yellow corner you change the center of Symmetry (Center / Opposite)

But maybe i don't understand the question :)
Can you post an image or a 3dm file ?

EDITED: 11 May 2012 by PILOU