public string Serialize()
{
string xml = "";
if (avsResult != null) xml += "\r\n<avsResult>" + SecurityElement.Escape(avsResult) + "</avsResult>";
if (cardValidationResult != null) xml += "\r\n<cardValidationResult>" + SecurityElement.Escape(cardValidationResult) + "</cardValidationResult>";
if (authenticationResult != null) xml += "\r\n<authenticationResult>" + SecurityElement.Escape(authenticationResult) + "</authenticationResult>";
if (advancedAVSResult != null) xml += "\r\n<advancedAVSResult>" + SecurityElement.Escape(advancedAVSResult) + "</advancedAVSResult>";
return xml;
}