code: public void initiate(final AjaxRequestTarget target)
  	{
  		String url = getCallbackUrl().toString();
  
  		if (antiCache)
  		{
  			url = url + (url.contains("?") ? "&" : "?");
  			url = url + "antiCache=" + System.currentTimeMillis();
  		}
  		// the timeout is needed to let Wicket release the channel
  		target.appendJavaScript("setTimeout(\"window.location.href='" + url + "'\", 100);");
  	}
docs: Call this method to initiate the download.
  
  @param target
  the {@link AjaxRequestTarget}