1. A system for extending a web service environment to support scalable asynchronous clients, comprising: one or more computers that provide a service, such as a web service, which is configured to generate responses to requests from clients; a client environment which includes a client application to communicate requests to the service via a client proxy; and wherein to make a request, the client application invokes on an asynchronous client transport feature to send a request message to the service, the client proxy automatically deploys a response endpoint which is associated with an endpoint reference (EPR), and which will ultimately receive the response, and when the service subsequently generates a response message, that response is provided to the response endpoint indicated by the EPR, where it can be correlated with the original request, and returned to the invoking client.