Embed an XML-based php script into c# which send parameters to another php file

Does anyone know how to embed the following php script into a c# webpage which would pass a user ID and password to another php file called "results.php" which would display the records of a MySQL database in XML-format? //-----------------------------------------

<Orders> <Login> <UserID>BV</UserID> <Password>secretPW</password> <SessionID></SessionID> </Login> <RequestGetOrder> <Id></Id> </RequestGetOrder> </Orders>

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