if(is_array($arParams["MENU_CACHE_GET_VARS"])) 
   { 
      foreach($arParams["MENU_CACHE_TIME"] as $varname) 
      { 

<?
// пример файла .left.menu_ext.php

if(!defined("B_PROLOG_INCLUDED") || B_PROLOG_INCLUDED!==true)die();

global $APPLICATION;

$aMenuLinksExt = $APPLICATION->IncludeComponent(
   "bitrix:menu.sections",
   "",
   Array(
      "ID" => $_REQUEST["ELEMENT_ID"], 
      "IBLOCK_TYPE" => "books", 
      "IBLOCK_ID" => "30", 
      "SECTION_URL" => "/e-store/books/index.php?SECTION_ID=#ID#", 
      "CACHE_TIME" => "3600" 
   )
);

$aMenuLinks = array_merge($aMenuLinks, $aMenuLinksExt);

?>