[Dovecot] Warn before overquota

Looking in the archives I found a message from dominik.saar@1und1.de on the 16/08/06, that is asking for a system to control the overquota warnings from within dovecot or dovecot LDA. The proposed solution is to use exim as MTA, since it has build in support. In my case I'm using postfix, what would be the recommended approach in that case? I was thinking of something like the cyrus LDA that you can with deliverquota [ -w percent ], something like that in a quota aware LDA would be quite useful for me. Any proposed solution would be welcome.

Thanks