In order for this to be "solved" by GWT 2, you need to be using RequestFactory instead of GWT-RPC.
http://code.google.com/webtoolkit/doc/latest/DevGuideRequestFactory.html List, Set and Collection will be properly copied to a shim when using this facility -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-web-toolkit/-/6JD0lFmmqQUJ. To post to this group, send email to google-web-toolkit@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.