Did you ever get an answer on this? I export from CC8 to make my .puz files, and the resulting .puz file has no circles-in-squares.
I contacted Anthony Lewis (who replied immediately) and he suggested I might use Across Lite's XML file format (files exported from CC8 appear to be some uneditable binary format).
Not being able to find that spec online, I contacted Litsoft for more information but no reply.
So any help appreciated...