[Dovecot] How to call a script when an E-Mail will moved in a folder?

[Luca Bertoncello]

Hi, list!

I use Dovecot 1.1.14 at work. It is configured to manage IMAP and IMAPs.
Exim is the MTA of the Network.

Of course, I installed SpamAssassin and ClamAV to check all incoming E-Mails.

An, of course, some E-Mail marked as Spam are Ham and some E-Mail marked as Ham
are Spam...

To teach SpamAssassin I create for every user two folder: "DochSpam" (for Spam
E-Mails not marked) and "FalscheSpam" (for Ham E-Mails marked as Spam).

Every hour a cronjob search for E-Mails in these folders and call sa-learn to
teach SpamAssassin.

All run perfectly, but I'd like to modify this method and call automatically
the script when the user move an E-Mail to DochSpam or FalscheSpam.

I searched in Google, but I cannot found any useful link...

How can I trigger an action (script calling) based on event (E-Mail will be
moved to a folder) in Dovecot?

Thanks for your help!
Luca Bertoncello
(lucabert at lucabert.de)