how to test GWT app through a proxy

I have several GWT (2.4) applications out there.

One in a while, a user writes in with a problem,
where it is clear the RPC is not working, and it
is clear there is some proxy involved in their access
to the application.

(Most recent: "Unable to initiate the asynchronous service invocation
(MyDataService_Proxy.login)")

I need to figure out some way to test access to the
applications through a proxy, so I can at least see what
these users are seeing. The same applications work fine
for me on a variety of browsers and computers.
(My own computers get to the web through ATT DSL with
no proxy involved.)

Has anyone else faced this problem (need to test through
a proxy)?

--
You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group.
To post to this group, send email to google-web-toolkit@googlegroups.com.
To unsubscribe from this group, send email to google-web-toolkit+unsubscribe@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.