Are you sure about that? Cache-Control, Expires? If you don't change the URL IE will cache the response whether you like it or not. 2 ways to handle this are to generate a random number to append as a parameter to change the URL. The other way is to have your web service to tell the browser not to cache with response headers. I have had IE do this to me and made all my web services send back "Cache-Control: no-cache" to prevent IE caching.
