Searching for a Sieve web Autoreplier OR Outlook solution

[Adam Tauno Williams]

>I'm searching for months without success for either one of these solutions :
>a) Out-of-office (away) plugin for Outlook that would use Sieve ?

No idea.

>b) Web interface to manage an out-of-office message in Sieve ?

Horde's Ingo provides a very nice web interface for configuring various, including SIEVE, mail 
filters.   There is also the old (unmaintained?) SmartSIEVE application.