public function refund($Card, $amount, $salestax = null, $comment = null, $is_card_present = false, $is_ecommerce = true, $force_new_transaction = true)
	{
		$this->_setError(QuickBooks_MerchantService::ERROR_OK);
		$this->_log('refund()', QUICKBOOKS_LOG_VERBOSE);
		
		if (!$this->isSignedOn())
		{
			$this->signOn();
			
			if ($this->errorNumber())
			{
				return false;
			}
		}
		
		// Error checking
		if (!($Card instanceof QuickBooks_MerchantService_CreditCard))
		{
			$this->_setError(QuickBooks_MerchantService::ERROR_PARAM, 'refund() expects first parameter to be a Card object, got: ' . print_r($Card, true));
			return false;
		}
		
		if (!is_numeric($amount))
		{
			$this->_setError(QuickBooks_MerchantService::ERROR_PARAM, 'refund() expects second parameter to be a float, got: ' . print_r($amount, true));
			return false;
		}
		
		$transRequestID = $this->_transRequestID(QuickBooks_MerchantService::TYPE_REFUND, $Card, $amount, $force_new_transaction);
		
		$xml = '';
		$xml .= '<?xml version="1.0" encoding="utf-8"?>' . QUICKBOOKS_CRLF;
		$xml .= '<?qbmsxml version="4.1"?>' . QUICKBOOKS_CRLF;
		$xml .= '<QBMSXML>' . QUICKBOOKS_CRLF;
		$xml .= $this->_createSessionXML();
		$xml .= '	<QBMSXMLMsgsRq>' . QUICKBOOKS_CRLF;
		$xml .= '		<CustomerCreditCardRefundRq>' . QUICKBOOKS_CRLF;
		$xml .= '			<TransRequestID>' . $transRequestID . '</TransRequestID>' . QUICKBOOKS_CRLF;
		
		//                                  $Card, $amount, $salestax, $is_card_present, $is_ecommerce, $is_recurring, $is_mobile, $include_address_data = true, $include_amounts = true, $include_card_number = true, $include_card_cvv = true, $include_card_dates = true
		$xml .= $this->_createCreditCardXML($Card, $amount, $salestax, $is_card_present, $is_ecommerce, false,         null, false,                        true,                    true,                        false);
		
		//<BatchID >STRTYPE</BatchID> <!-- optional -->

		if ($comment)
		{
			$xml .= '			<Comment>' . substr(QuickBooks_XML::encode($comment), 0, 500) . '</Comment>' . QUICKBOOKS_CRLF;
		}

		$xml .= '		</CustomerCreditCardRefundRq>' . QUICKBOOKS_CRLF;
		$xml .= '	</QBMSXMLMsgsRq>' . QUICKBOOKS_CRLF;		
		$xml .= '</QBMSXML>' . QUICKBOOKS_CRLF;
		
		return $this->_doQBMS(QuickBooks_MerchantService::TYPE_REFUND, 'QBMSXML/QBMSXMLMsgsRs/CustomerCreditCardRefundRs', $xml, $Card);
	}