Setting a response header in a CQ5 publishing instance

I want to disable caching in a CQ component and I have the following line in my jsp (documentation):

response.setHeader("Dispatcher", "no-cache"); 

If I insert the component in a page and load the page in an authoring instance everything works as expected and I get an HTTP header named Dispatcher with the content no-cache.

Now if I do the same on a publishing instance (same configuration with CQ_RUNMODE='publish' and same content) the component works but for setting the HTTP header.

Any idea on why the two instances could behave differently?