On his blog, <A HREF="http://www.codestore.net/store.nsf/unid/BLOG-20081008">Jake Howlett</A> walks through the steps to implement a login interface for an Ext-based Domino application. In order to avoid the user seeing anything other than a pretty-looking Ext app he uses Ajax requests to log the user in. He ends his discussion with a demo you can view/copy.