Establishing context for menus in nodes
  //establish context
  switch ($node->type) {
    case 'product':
     $path = 'products';
    break;
  //.....                                       
    default:
      $path = false;
    break;
  }
  if ($path) {
    menu_set_active_trail(menu_get_item($path)); 
    $tree = menu_tree_all_data('primary-links');
  } else {
     $tree = menu_tree_page_data('primary-links');
  }
  foreach($tree as $key => $mi) {
    if ($mi['link']['in_active_trail'] || $path == $mi['link']['link_path']) {
      $menu = menu_tree_output($tree[$key]['below']);                  
    }
  }
