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 /channels/{Channel}/object HTTP/1.1 
Host: test.servicestack.net 
Accept: application/xml
Content-Type: application/xml
Content-Length: length
<PostObjectToChannel xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/Test.ServiceInterface">
  <Channel>String</Channel>
  <CustomType>
    <Id>0</Id>
    <Name>String</Name>
  </CustomType>
  <Selector>String</Selector>
  <SetterType>
    <Id>0</Id>
    <Name>String</Name>
  </SetterType>
  <ToUserId>String</ToUserId>
</PostObjectToChannel>