diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index ae01f86d..9576a834 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -19,13 +19,22 @@ class ApplicationController < ActionController::Base
     Wiki.new
   end
 
+  helper_method :xhtml_enabled?, :html_ext
+
   protected
 
   def xhtml_enabled?
     in_a_web? and [:markdownMML, :markdownPNG, :markdown].include?(@web.markup)
   end
 
-  helper_method :xhtml_enabled?
+  def html_ext
+    if xhtml_enabled? && request.env.include?('HTTP_ACCEPT') &&
+           Mime::Type.parse(request.env["HTTP_ACCEPT"]).include?(Mime::XHTML)
+       'xhtml'
+    else
+      'html'
+    end       
+  end
 
   def check_authorization
     if in_a_web? and authorization_needed? and not authorized?
diff --git a/app/controllers/wiki_controller.rb b/app/controllers/wiki_controller.rb
index 270fbebd..b4d247f2 100644
--- a/app/controllers/wiki_controller.rb
+++ b/app/controllers/wiki_controller.rb
@@ -380,15 +380,6 @@ class WikiController < ApplicationController
     end
   end
 
-  def html_ext
-    if xhtml_enabled? && request.env.include?('HTTP_ACCEPT') &&
-           Mime::Type.parse(request.env["HTTP_ACCEPT"]).include?(Mime::XHTML)
-       'xhtml'
-    else
-      'html'
-    end       
-  end
-
   protected
 
   def do_caching?
diff --git a/lib/url_generator.rb b/lib/url_generator.rb
index 25b7f757..5fc4e355 100644
--- a/lib/url_generator.rb
+++ b/lib/url_generator.rb
@@ -64,7 +64,7 @@ class UrlGenerator < AbstractUrlGenerator
     case mode
     when :export
       if known_file
-        %{<a class="existingWikiWord" title="#{description}" href="#{CGI.escape(name)}.#{@controller.html_ext}">#{text}</a>}
+        %{<a class="existingWikiWord" title="#{description}" href="#{CGI.escape(name)}.#{html_ext}">#{text}</a>}
       else 
         %{<span class="newWikiWord">#{text}</span>}
       end
@@ -92,7 +92,7 @@ class UrlGenerator < AbstractUrlGenerator
     case mode
     when :export
       if known_page 
-        %{<a class="existingWikiWord" href="#{CGI.escape(name)}.#{@controller.html_ext}">#{text}</a>}
+        %{<a class="existingWikiWord" href="#{CGI.escape(name)}.#{html_ext}">#{text}</a>}
       else 
         %{<span class="newWikiWord">#{text}</span>} 
       end
@@ -181,5 +181,11 @@ class UrlGenerator < AbstractUrlGenerator
       href = @controller.url_for :controller => 'wiki', :web => web_address, :action => action, 
             :id => name, :only_path => true
       %{<a class="existingWikiWord" href="#{href}">#{text}</a>}
-    end  
+    end
+    
+    def html_ext
+      @html_ext ||= @controller.method(:html_ext).call
+      # Why method().call ? A Ruby 1.9.2preview1 bug:
+      # http://redmine.ruby-lang.org/issues/show/1802
+    end
 end