If a WSDL file already exists when you have decided an interface, you can use a command (iswsgen) provided by Interstage Application Server to create a Web service application.
However, this command does not automatically create a deployment descriptor. Therefore, you would have to create a deployment descriptor.
For details on this command and on development using the command, refer to the "Interstage Application Server J2EE User's Guide" or the "Interstage Application Server Reference Manual (Command Edition)".