protected function _initItems()
    {
        if (!$this->_itemsXmlPath) {
            throw new RuntimeException('XML Path for facade items is not specified');
        }
        
        $config = Mage::getConfig()->getNode($this->_itemsXmlPath)->children();
        
        foreach ($config as $class) {
            $this->add(Mage::getModel($class));
        }
        
        return $this;
    }