XML Serialize ederken şema sorunu

 
   private static XmlSerializerNamespaces _InvoiceNamespaces; 
          public static XmlSerializerNamespaces InvoiceNamespaces 
          { 
              get 
              { 
                  if (_InvoiceNamespaces == null) 
                  { 
                      _InvoiceNamespaces = new XmlSerializerNamespaces(); 
                      _InvoiceNamespaces.Add("", "urn:oasis:names:specification:ubl:schema:xsd:Invoice-2"); 
                      _InvoiceNamespaces.Add("ext", "urn:oasis:names:specification:ubl:schema:xsd:CommonExtensionComponents-2"); 
                      _InvoiceNamespaces.Add("cac", "urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2"); 
                      _InvoiceNamespaces.Add("cbc", "urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2"); 
                      _InvoiceNamespaces.Add("cctc", "urn:un:unece:uncefact:documentation:2"); 
                      _InvoiceNamespaces.Add("ds", "http://www.w3.org/2000/09/xmldsig#"); 
                      _InvoiceNamespaces.Add("qdt", "urn:oasis:names:specification:ubl:schema:xsd:QualifiedDatatypes-2"); 
                      _InvoiceNamespaces.Add("ubltr", "urn:oasis:names:specification:ubl:schema:xsd:TurkishCustomizationExtensionComponents"); 
                      _InvoiceNamespaces.Add("udt", "urn:un:unece:uncefact:data:specification:UnqualifiedDataTypesSchemaModule:2"); 
                      _InvoiceNamespaces.Add("xades", "http://uri.etsi.org/01903/v1.3.2#"); 
                      _InvoiceNamespaces.Add("xsi", "http://www.w3.org/2001/XMLSchema-instance"); 
                  } 
                  return _InvoiceNamespaces; 
              } 
          }