1. A method in a Web service provider communicatively interfaced with a plurality of Web service clients, comprising: obtaining a description of a Web service comprising protocol-independent business logic; generating a Web service client proxy based, at least in part, on the description obtained, wherein the generated Web service client proxy comprises the protocol-independent business logic in an executable format and is extended with one or more client protocol implementations; generating a first virtual interface to the Web service based on the description obtained, the first virtual interface comprising a mapping of the protocol-independent business logic of the Web service to a first transport protocol that provides a first Web service client access to the protocol-independent business logic of the Web service, and wherein the first Web service client comprises a Web service client authentication extension having a user selectable authentication protocol therein for specifying the authentication protocol to be implemented by the Web service client proxy between the virtual interface and the first Web service client, without regenerating the Web service client proxy; receiving and implementing the user specified authentication protocol without regenerating the Web service client proxy, wherein the user specified authentication protocol is received from the first Web service client via a logical port between the first Web service client and the Web service client proxy; processing message traffic exchanged between the Web service client proxy and the first Web service client via the first virtual interface in accordance with the first transport protocol and the user specified authentication protocol implemented by the Web service client proxy; generating a second virtual interface to the Web service based on the description obtained, the second virtual interface comprising a mapping of the protocol-independent business logic of the Web service to a second transport protocol different than the first transport protocol, wherein the second virtual interface to provide a second Web service client access to the protocol-independent business logic of the Web service without regenerating the Web service; and processing message traffic exchanged between the Web service client proxy and the second Web service client via the second virtual interface in accordance with the second transport protocol, and in accordance with a second user selectable authentication protocol received and implemented without regenerating the Web service client proxy.