dovecot - Jan 2013 - Fts Search

Hello, i'm trying to search in mails which are in russian language. Search
works fine for UTF-8 mails, but it ignores KOI8-R ones. For english in any 
mails it also works fine. How i can solve it?
I have dovecot 1.2.17 and following config for fts:
protocol imap {
  .....
  mail_plugins = quota imap_quota autocreate fts fts_squat
}
plugin {
 ...
 fts = squat
 fts_squat = partial=4 full=10
}