hook_form_alter for empty_value not working

On a Webform, without the "Select (or other)" module, one can change the default text on a required select list from "- Select" to custom text like so (see https://drupal.org/node/1331956):

function yourmodule_form_alter(&$form, &$form_state, $form_id) {
  switch($form_id) {
      
    case 'webform_client_form_your_webform_id':
            $form['submitted']['component_name']['#default_value'] = '';
            $form['submitted']['component_name']['#empty_value'] = '';
            $form['submitted']['component_name']['#empty_option'] = '- Select country -'; 

            break;
  }
}

This code does nothing when the "Select (or other)" module "Allow 'Other...' option" is used.