std::tstring GetDefaultNamespaceURI() const
void SetDefaultNamespaceURI(LPCTSTR lpctNS)
 PropertyDescription 
  Property NameDefaultNamespaceURI  
  Property Type string  
  Accessors Read/Write  
  DescriptionSpecifies the default namespace used in the output  
  Remarks In the example “http://sample” was the value.

<?xml version="1.0" encoding="UTF-8"?>
<Invoice xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns="http://sample">