I'd like to resurrect this thread, since we got +1 votes from just about everyone who replies on a a regular basis.
"If the JSF container is used in a Servlet 3 (or newer) environment, it should register an implementation of ServletContainerInitializer (using Service Providers from the JAR file specification). The ServletContainerInitializer should register the FacesServlet, with a name of Faces Servlet, if an existing servlet is not yet registered with this name. Furthermore, a suffix mapping of *.jsf and a prefix mapping of /faces/* should be added."