Webform custom submit handler rebuild
I think I've just used $form_state['redirect'] in the submit handler in the past.

However I'm not sure what order your submit handlers are firing in, maybe it would work if you added the after_build function to the form array as opposed to the button array. (If your custom submit handler is firing first then your redirect could get overwritten.)

E.g: $form['#submit'][] = 'he_helper_custom_redirect';


If that doesn't work then this post suggests using rebuild with redirect:

$form_state['redirect'] = 'where-do-you-want-to-go-today';
$form_state['rebuild'] = TRUE;


This code shows how to add a new custom submit handler without overwriting the original one:

function he_helper_after_build(&amp;$form, &amp;$form_state) {

  // add to the existing submit array to not override the default submit handler
  $form['actions']['submit']['#submit'][] = '_he_helper_custom_submit';

  // change the button text
  $form['actions']['submit']['#value'] = '2hello';

  return $form;
}