Web application session while using RESTish web services

I am into a project with front-end as SmartClient AJAX RIA framework and spring-jpa-hibernate at server end. All server APIs are exposed as RESTish services.

My problem is that when ever GUI is idle for over 10 minutes, server terminates my web session and serve my next request with 401 response (un-authorized access).

I tried below settings in my web.xml

<session-config>
    <sessio开发者_StackOverflow社区n-timeout>30</session-timeout>
</session-config>

but still my web session expires in nearly 10 mins.

Any idea?

please provide details on the type of server used to deploy.. many app servers have an option to override the session timeout during deployment phase..

I've worked extensively with Websphere (which has this feature)...