Added message from #5008

Author: wouterj

reference/configuration/framework.rst

@@ -120,8 +120,9 @@ http_method_override
 This determines whether the ``_method`` request parameter is used as the intended
 HTTP method on POST requests. If enabled, the
 :method:`Request::enableHttpMethodParameterOverride <Symfony\\Component\\HttpFoundation\\Request::enableHttpMethodParameterOverride>`
-method gets called automatically. It becomes the service container parameter
-named ``kernel.http_method_override``.
+method gets called automatically, unless the application uses a kernel based on
+the cache, where you need to invoke that method manually (see
+:ref:`symfony2-reverse-proxy` for details).
 
 .. seealso::