SSL Error:
Does it happen for this user every time you try to access the account, from any computer? Or just the one computer? Is IMAP access disabled for that user?
File Copy:
The only way to prevent "unauthorized duplication" would be the same way you prevent unauthorized copying of any other filers: prevent users from having access to places to put those files. beyond that there are a few things you could do, all depending on how restrictive you really want to get...
Signatures/Filters:
If you are connecting to a Zimbra server I believe those are synced to the server. For other account types I think this is stored in the derby database located at <zd install path>\derby but I could easily be wrong
