Index: smtp.module
===================================================================
--- smtp.module	(Revision 881)
+++ smtp.module	(Arbeitskopie)
@@ -368,6 +368,13 @@
         elseif (strpos(drupal_strtolower($value), 'text/html') !== FALSE) {
           // The message includes only an HTML part.
           $mail->IsHTML(TRUE);
+
+          // Set the charset based on the provided value, if there is one.
+          $charset = _smtp_get_substring($value, 'charset', '=', ';');
+          if ($charset) {
+            $mail->CharSet = $charset;
+          }
+
           $content_type = 'text/html';
         }
         elseif (strpos(drupal_strtolower($value), 'multipart/related') !== FALSE) {