public function isAvailable( MShop_Order_Item_Base_Interface $base )
	{
		if( ( $prodcode = $this->_getConfigValue( 'required.productcode' ) ) !== null )
		{
			foreach( $base->getProducts() as $product )
			{
				if( $product->getProductCode() == $prodcode ) {
					return parent::isAvailable( $base );
				}
			}

			return false;
		}

		return true;
	}