Form Authentication Login Page

Using MS VisualStudio.Net 2005, developing an ASP.Net web application with forms authentication [VS.Net builtin web server], then look further.
Wonder why the login page images / style sheets are not loaded in forms
authentication.
This is because the built in webserver passes all request through ASP.Net.
For futher details http://weblogs.asp.net/scottgu/archive/2006/01/31/437027.aspx