code: public void callService(String url, String templateName, Object model, XmlHttpResponse result) {
          callService(url, templateName, model, result, null);
      }
docs: Performs POST to supplied url of result of applying template with model.
  All namespaces registered in this environment will be registered with result.
  @param url url to post to.
  @param templateName name of template to use.
  @param model model for template.
  @param result result to populate with response.