[Dovecot] best practice to have sent mail folder on dovecot imap server

[Thomas Koch]

I've already asked this here:
http://serverfault.com/questions/533940/best-practice-to-have-sent-mail-
folder-on-dovecot-imap-server

Hi,

when I add a mail account to KMail (or most other MUA I suppose) the sent mail 
folder is on the local machine and I don't have my sent mails on other 
machines.

I'd like to have a sent mail folder in IMAP and I thought that there would 
already exist a standard or best practice how to set this up so that the mail 
is only transfered once to the MTA and from the MTA to the IMAP server.

I even thought to remember an RFC related to this problem?

It isn't that simple, is it? I'm using Exim.

Regards, Thomas Koch