[Exim] Vacation Tool

Dear folks,

I wonder if there is a fine vacation tool somewhere that works
good with exim?!

The requirements are e.g. that I can't use .vacation files because
the users don't have an own home directory AND that the
the users might set and remove the vacation message by sending
an email to a robot or anything else.

Any hints? Else I have to sit down and write one my own.

Regards,
Sascha

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Sascha E. Pollok
Network Operations / Internet Port Hamburg
Grosse Reichenstrasse 27
D-20457 Hamburg
Germany
Tel. +49 40 37 49 19-0
Fax +49 40 37 49 19-29
Email sp@???