[Dovecot] Logging IMAP transactions

Mulberry has the ability to log the IMAP exchange client-side. Is there an equivalent logging feature in Dovecot (0.99) to log the IMAP exchange server-side?

My problem is that Mulberry is displaying some complex MIME structures incorrectly (eg. nested/forwarded messages) but it seems to go away if I close a folder and re-open it. I'm suspecting that Dovecot is reporting the wrong structure on first access and then fixes something on subsequent accesses. I'd like to log the FETCH result with the structure information to see if I can spot this happening.