Combining facelets and jsp's in one webapplication requires some special custom
settings in web.xml. Because the JSF sepc allows only one ViewHandler per
application, the Facelets ViewHandler delegates to his parent ViewHandler when
the request is mapped to a JSP in stead of a facelet.
It would be more elegant to have more than one ViewHandler per webapplication.
This could work on url mapping possibly using faces config in stead of web.xml
to allow for a more powerful mapping mechanism (eg regular expressions). People
who have worked with Cocoon will understand how powerful that can be.