diff --git a/app/models/mailer.rb b/app/models/mailer.rb
index 7fab66e..7696668 100644
--- a/app/models/mailer.rb
+++ b/app/models/mailer.rb
@@ -392,7 +392,7 @@ class Mailer < ActionMailer::Base
     ActionMailer::Base.delivery_method = saved_method
   end
 
-  def mail(headers={})
+  def mail(headers={}, &block)
     headers.merge! 'X-Mailer' => 'Redmine',
             'X-Redmine-Host' => Setting.host_name,
             'X-Redmine-Site' => Setting.app_title,
@@ -426,12 +426,16 @@ class Mailer < ActionMailer::Base
       headers[:references] = @references_objects.collect {|o| "<#{self.class.message_id_for(o)}>"}.join(' ')
     end
 
-    super headers do |format|
-      format.text
-      format.html unless Setting.plain_text_mail?
-    end
-
     set_language_if_valid @initial_language
+
+    if block_given?
+      super headers, &block
+    else
+      super headers do |format|
+        format.text
+        format.html unless Setting.plain_text_mail?
+      end
+    end
   end
 
   def initialize(*args)