How to add to 'Secondary Local Tasks' on Order page
Just emulate what you see in the other modules:

  if (module_exists('commerce_order_ui')) {
    $items['admin/commerce/orders/%commerce_order/edit/refresh'] = array(
      'title' =&gt; 'Apply pricing rules',
      'description' =&gt; 'Executes the cart order refresh used to apply all current pricing rules on the front end.',
      'page callback' =&gt; 'drupal_get_form',
      'page arguments' =&gt; array('commerce_cart_order_refresh_form', 3),
      'access callback' =&gt; 'commerce_cart_order_refresh_form_access',
      'access arguments' =&gt; array(3),
      'type' =&gt; MENU_LOCAL_ACTION,
      'file' =&gt; 'includes/commerce_cart.admin.inc',
    );
  }


The important thing is the type and the path.