Just making sure....
On the DH email address setup page, the section about removing messages when a certian number of emails is reached or email age is reached...
"(Tidy inboxes keep mail servers happy!)
Remove read messages when inbox reaches X messages.
Remove read messages from inbox older X than days."
... this only effects your "inbox" correct? For example, email moved from an IMAP inbox to another IMAP folder will not be affected (except by of course, disk quotas)?
Whould hate to see email start to disappear once one of these limits are reached.