To override the Content-type in your clients, use the HTTP Accept Header, append  the .xml suffix or  ?format=xml
 
		
        
        HTTP + XML
         The following are sample HTTP requests and responses. 
            The placeholders shown need to be replaced with actual values.
POST /xml/reply/HelloWithInheritance HTTP/1.1 
Host: test.servicestack.net 
Accept: application/xml
Content-Type: application/xml
Content-Length: length
<HelloWithInheritance xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/Test.ServiceModel">
  <Id xmlns="http://schemas.datacontract.org/2004/07/Test.ServiceModel.Types">0</Id>
  <Name>String</Name>
</HelloWithInheritance>
 
HTTP/1.1 200 OK
Content-Type: application/xml
Content-Length: length
<HelloWithInheritanceResponse xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/Test.ServiceModel">
  <RefId xmlns="http://schemas.datacontract.org/2004/07/Test.ServiceModel.Types">0</RefId>
  <Result>String</Result>
</HelloWithInheritanceResponse>