[Dovecot] Best way to migrate from qmail-ldap's autoreply?

Hi,

qmail-ldap uses four LDAP attributes for handling autoreplies in qmail-local:

• deliverymode (to see whether the autoreply should be send)
• mailreplytext, which is a base64 encoded multiline string*
• mailreplystart and mailreplystop, unix dates

I'm wondering how this could be handled with Dovecot (2.0) in the most easier way. All I could find out so far: the first glimpse)

• patching the code
• writing a plugin (it it possible to get these LDAP attributes in the LMTPd with a single userdb-lookup and get it from the plugin during a new mail event? Any examples?)
• conditionally provide these values to a sieve script and process them accordingly (the base64 string and maybe the dates seem to be hard for

the mad stuff: the Dovecot LMTPd/deliver process

• using an LD_PRELOAD library, which emulates per user sieve scripts according to LDAP lookups (gives a lot more flexibility)
• an LMTP proxy/server, which does all this and forwards the traffic to

• a sample mailreplytext looks like this: '''%HEADER% Content-type: text/plain; charset="utf-8"

távol vagyok'''

(of course this is in UTF-8).