1. A method for extending a schematized XML protocol, comprising: identifying, by a client application running on a client processor, first data to be transmitted to a server application running on a server processor, the first data identified using a standard XML protocol schema, and second data to be transmitted to the server application, the second data not defined in the standard XML protocol schema; and generating, by the client application on the client processor, a message comprising the first data using elements available in the standard XML protocol schema, and comprising the second data using XML annotation elements.