Please elaborat on the use case, why is the wsdl so secret?
the reason for protecting the wsdl file, is that the wsdl file can give
valuable information for starting a Web Service related attack,
according to the bibliography (see for example: Hacking Exposed, Web Applications, Scambray J., Shema M., McGraw Hill; Hacking Exposed,
J2EE & Java, Taylor B., Buege R., Layman A., McGraw Hill).