reverse proxy issue with rpc

I have the following problem:
- I have a web application installed on a customer's server and running with jetty at /ksatweb. The application module is named kweb.
- the application is available on the web through a reverse proxy and mapped to https://portal.ksat.no/ordering/ksatweb/

The issue I get is when using rpc. Below is the error message I get. I tried many work arounds, found by googling the issue but none worked, eg I have no control over the proxy configuration so the use of headres is not possible, etc... If anybody has an idea how to get me out of there, I am ready to do some dirty hack to get this to work...

Thanks in advance,

2012-06-27 16:16:11.752:INFO:/ksatweb:ResourcesService: ERROR: The module path r
equested, /ordering/ksatweb/kweb/, is not in the same web application as this se
rvlet, /ksatweb.  Your module may not be properly configured or your client and
server code maybe out of date.
2012-06-27 16:16:11.752:INFO:/ksatweb:ResourcesService: WARNING: Failed to get t
he SerializationPolicy '2225236803D085D4C928146663661808' for module 'https://po
rtal.ksat.no/ordering/ksatweb/kweb/'; a legacy, 1.3.3 compatible, serialization
policy will be used.  You may experience SerializationExceptions as a result.
2012-06-27 16:16:11.768:WARN:/ksatweb:Exception while dispatching incoming RPC c
all
com.google.gwt.user.client.rpc.SerializationException: Type 'com.metaaps.webapps
.ksatweb.shared.entity.User' was not assignable to 'com.google.gwt.user.client.r
pc.IsSerializable' and did not have a custom field serializer.For security purpo
ses, this type will not be serialized.: instance = com.metaaps.webapps.ksatweb.s
hared.entity.User@371d6be8

--
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/-/bXQD1IY6DesJ.
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.