URLRedirectForwardAction does a HTTP302 to another page, which means your RequestContext (and HttpServletRequest) are completely new objects by the time your target page gets rendered. What you're looking for is an internal forward, and LiveSite doesn't provide that type of functionality. What you'll have to do is construct your own URL object and give the query string parameters you want to preserve, then call the URLRedirectForwardAction(URL url) constructor.