yes i used AuthenticationApplication as a root of my WorkSpace Application
<?xml version="1.0" encoding="utf-8"?>
<lc:AuthenticatingApplication
xmlns:mx="http://www.adobe.com/2006/mxml"
xmlns:lc="http://www.adobe.com/2006/livecycle"
xmlns:cc="custComp.*"
layout="absolute">
<cc:CustNavigator session="{session}" width="100%" height="100%"/>
</lc:AuthenticatingApplication>