Widget client-server integration

Hi

For my application I need server-side component to prepare different data in UIDL if client side component is new (first time run updateFromUIDL) and different data in the opposite case. Problem is lifetime of serverside component is session-wide, while on cleint side component might by unLoaded and new one created while navigating application in browser.

Is it possible to notify serverside component that on client side new component was created, are there some listeners maybe or something like that? Or maybe some other way to make stateful client side components easier?