[Dovecot] Sieve, vacation, variables and russian language

Folks,

I'm using a Sieve script for vacation messages and there's something strange with it in certain cases.

The script uses the "variables" extension to produce the "Re: [original subject] (autoreply)" subject line for the vacation message.

All is well except for cases when that [original subject] is written in Russian.

In those cases the subject string is garbled, and the Amavis content filter says

"X-Amavis-Alert: BAD HEADER SECTION, Non-encoded 8-bit data (char D0 hex):Subject: RE: \320\277\321?\320\276\320\261\320\260 (Auto[...]"

It doesn't complain about English subject strings, though.

I've seen the thread about "Sieve vacation with russian subject" at http://www.dovecot.org/list/dovecot/2009-July/041031.html ,

but that wasn't quite a solution.

I can't figure out how to work around that, could anyone help out please?

Mandatory info:

FreeBSD 7.2 i386, dovecot 1.2.3, dovecot-sieve-1.2+0.1.11

And here's the script itself:

require ["fileinto", "vacation", "variables"];

set "subject" "";

if header :matches "subject" "*" {

  set "subject" "${1}";

}

vacation :days 1 :subject "RE: ${subject}"

"[vacation message text]";

P.S. Stephan Bosch, thank you very much for what you've done with sieve.