Charset in voicemail.conf does not applying

The trouble is that when i’m trying to change encoding nothing happens with email subject and sender name. They looks like Ð¢ÐµÐ»ÐµÑ„Ð¾Ð½Ð½Ð°Ñ Ð¡Ñ‚Ð°Ð½Ñ†Ð¸Ñ (russian text there), even while default: CP-1251 or default: UTF-8.
But the message body is in correct charset.

What am I doing wrong, the aim is correct subject and sender name.