[Dovecot] Sieve plugin: Filtering UTF-8 Emails

[micha at pocomail.de]

hi all,

i hope it´s okay for questions about the sieve plugin here...
my problem is, that the filters do not seem to match utf8-content

for instance: the email:

Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: quoted-printable
Subject: 
=?utf-8?Q?Erinnerung:=20Bitte=20f=C3=BChren=20Sie=20die=20Kaufabwicklung=20durch?=

when i use the same subject (of course in utf-8) in my ".dovecot.sieve", 
the filter never matches ;-((

does anyone have an idea howto make the sample here matching by sieve ???

thank´s for any help!
michael