FedEx web services SOAP integration - how to display XML with markup / tags?

Hi all - having issues with this integration. I'm in contact with FedEx tech support and they need the XML generated by my script, however whenever I email or print xmlString all of the xml markup is removed and only the data contained within the tags is shown.

Anyone know how I can do this? I'll be happy to share what I'm doing wrong with FedEx SOAP integration when I figure it out with them.

xmlString = "";

xmlString = xmlString + "<soapenv:Envelope ";

xmlString = xmlString + "xmlns:soap=\" http://schemas.xmlsoap.org/soap/envelope/\" ";

xmlString = xmlString + "xmlns:v8=\" http://fedex.com/ws/vacs/v8\">";

xmlString = xmlString + "<soapenv:Header/>";

xmlString = xmlString + "<soapenv:Body>";

xmlString = xmlString + "<v8:ServiceAvailabilityRequest>";

xmlString = xmlString + "<v8:WebAuthenticationDetail>";

xmlString = xmlString + "<v8:ParentCredential>";

xmlString = xmlString + "<v8:Key>" + API_KEY + "</v8:Key>";

xmlString = xmlString + "<v8:Password>" + API_PASSWORD + "</v8:Password>";

xmlString = xmlString + "</v8:ParentCredential>";

xmlString = xmlString + "<v8:UserCredential>";

xmlString = xmlString + "<v8:Key>" + API_KEY + "</v8:Key>";

xmlString = xmlString + "<v8:Password>" + API_PASSWORD + "</v8:Password>";

xmlString = xmlString + "</v8:UserCredential>";

xmlString = xmlString + "</v8:WebAuthenticationDetail>";

xmlString = xmlString + "<v8:ClientDetail>";

xmlString = xmlString + "<v8:AccountNumber>" + API_ACCOUNTNUMBER + "</v8:AccountNumber>";

xmlString = xmlString + "<v8:MeterNumber>" + API_METERNUMBER + "</v8:MeterNumber>";

xmlString = xmlString + "</v8:ClientDetail>";

xmlString = xmlString + "<v8:TransactionDetail>";

xmlString = xmlString + "<v8:CustomerTransactionId>ServiceAvailabilityRequest</v8:CustomerTransactionId>";

xmlString = xmlString + "</v8:TransactionDetail>";

xmlString = xmlString + "<v8:Version>";

xmlString = xmlString + "<v8:ServiceId>vacs</v8:ServiceId>";

xmlString = xmlString + "<v8:Major>8</v8:Major>";

xmlString = xmlString + "<v8:Intermediate>0</v8:Intermediate>";

xmlString = xmlString + "<v8:Minor>0</v8:Minor>";

xmlString = xmlString + "</v8:Version>";

xmlString = xmlString + "<v8:Origin>";

xmlString = xmlString + "<v8:PostalCode>38017</v8:PostalCode>";

xmlString = xmlString + "<v8:CountryCode>US</v8:CountryCode>";

xmlString = xmlString + "</v8:Origin>";

xmlString = xmlString + "<v8:Destination>";

xmlString = xmlString + "<v8:PostalCode>05040</v8:PostalCode>";

xmlString = xmlString + "<v8:CountryCode>BR</v8:CountryCode>";

xmlString = xmlString + "</v8:Destination>";

xmlString = xmlString + "<v8:ShipDate>2016-02-23</v8:ShipDate>";

xmlString = xmlString + "<v8:CarrierCode>FDXE</v8:CarrierCode>";

xmlString = xmlString + "</v8:ServiceAvailabilityRequest>";

xmlString = xmlString + "</soapenv:Body>";

xmlString = xmlString + "</soapenv:Envelope>";

Thanks!