Note 1: even if you add introspection data via calls to `xmlrpc_server_register_introspection_callback` or `xmlrpc_server_add_introspection_data`, the server will not validate for you the number or type of received parameters.
This means that you have to implement all required validation of the received parameters in your php function.
Note 2: take care about dealing with base64 and datetime values in the received parameters: those are not automatically transformed into php scalar values, but into stdClass objects with members `xmlrpc_type` and `scalar`
