All emails sent from the server are displaying Cyrillic letters as weird characters, for example: Можно.

Regular alphabet letters are properly rendered.

I searched all across the web but was not able to find any solutions.

Here is some information about the system:

• Dedicated server with Windows 2008 and IIS7
• Application are in PHP (run as FastCGI)
• If of any importance, Smartermail is installed on the server

The emails are sent using PHPs mail() function through a Drupal website. Encoding on that site is set up properly and there are no display issues on front end.

Where is the problem? How can I make Cyrillic letters to be properly encoded?
Any help is greatly appreciated.

Thanks!

UPDATE

Here are the email headers:

Received: from SERVERNAME (mail.domain.com [12.123.123.123]) by mail.domain.com with SMTP; Fri, 16 Nov 2012 00:00:00 +0100
From: [email protected]
To: [email protected]
Subject: Email subject
Date: Fri, 16 Nov 2012 00:00:00 +0100
MIME-Version: 1.0
Content-Type: text/plain;
charset="utf-8"
Content-Transfer-Encoding: quoted-printable
X-Mailer: Drupal
Sender: [email protected]
Return-Path: [email protected]
Message-ID: f98b801988c642ef911ef46f7cace92b@com
X-SmarterMail-Spam: SPF_None, ISpamAssassin 8 [raw: 5], DK_None, DKIM_None, Custom Rules [] X-SmarterMail-TotalSpamWeight: 8