GWT RequestBuilder POST and XSS

I'm using GWT 2.1.1 and in my app there is a RequestBuilder/POST that fails (cross site scripting XSS). The main cause is the different urls for client and server:

client in dev-mode: http://127.0.0.1:8888/index.html?gwt.codesvr=127.0.0.1:9997#...

server jetty: http://localhost:8080/myapp/

so the browser (firefox in my case) "stops" the incoming post-request.

Is there a workaround (at least for de开发者_Go百科velopment) to continue using gwt in dev mode? I tried the proxy config:

http://code.google.com/p/google-web-toolkit/issues/detail?id=3131#c46

but nothing seems to happen :(

any idea?

Thanks, Julio