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/DataStoreRequest HTTP/1.1 
Host: api.paysecure.acculynk.net 
Accept: application/xml
Content-Type: application/xml
Content-Length: length
<DataStoreRequest xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.servicestack.net/types">
  <Credentials>
    <MerchantId>String</MerchantId>
    <Password>String</Password>
    <UserName>String</UserName>
    <Version>String</Version>
  </Credentials>
  <Scope>
    <StoreScope>AllMerchants</StoreScope>
    <Value>String</Value>
  </Scope>
</DataStoreRequest>
 
HTTP/1.1 200 OK
Content-Type: application/xml
Content-Length: length
<DataStore xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.servicestack.net/types">
  <ErrorCode>String</ErrorCode>
  <ErrorMessage>String</ErrorMessage>
</DataStore>