Without "-merge suffix=.alt", the same events occur up through step 4. In neither case am I able to complete the transfer without manual human intervention. :-(
You didn't say before that you wanted "without manual human intervention." Otherwise, I would use "-merge prompt" and choose an alternative name.
The whole issue is that there is no well-defined means to copy mailboxes from "dual-use" mail stores to regular mail stores.
-- Mark --
http://staff.washington.edu/mrc Science does not emerge from voting, party politics, or public debate. Si vis pacem, para bellum.