protected function _sortRootElements(Zend_Config $config)
    {
        $configArray = $config->toArray();
        $sections = array();

        // remove sections from config array
        foreach ($configArray as $key => $value) {
            if (is_array($value)) {
                $sections[$key] = $value;
                unset($configArray[$key]);
            }
        }

        // readd sections to the end
        foreach ($sections as $key => $value) {
            $configArray[$key] = $value;
        }

        return new Zend_Config($configArray);
    }