public function removeCustomerNo($custNo)
    {
        $this->_checkArgument($custNo, 'custNo');

        $digestSecret = self::digest(
            $this->colon($this->_eid, $custNo, $this->_secret)
        );

        $paramList = array(
            $custNo,
            $this->_eid,
            $digestSecret
        );

        self::printDebug('remove_customer_no', $paramList);

        $result = $this->xmlrpc_call('remove_customer_no', $paramList);

        return ($result == 'ok');
    }