protected static function convertSpecialGoalIds($idGoal)
    {
        if ($idGoal == Piwik::LABEL_ID_GOAL_IS_ECOMMERCE_ORDER) {
            return GoalManager::IDGOAL_ORDER;
        } else if ($idGoal == Piwik::LABEL_ID_GOAL_IS_ECOMMERCE_CART) {
            return GoalManager::IDGOAL_CART;
        } else {
            return $idGoal;
        }
    }