Yes, I have taglibs included and it is a jsf-enabled project:
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:rich="http://richfaces.org/rich"
xmlns:a4j="http://richfaces.org/a4j">
The page renders fine, the only (little) problem is, that no tag-proposals for jsf2-tags are shown while developing on the page.
jsf-1.1-tags for f and u are regogniced while typing, but not jsf2-tags is missing, so I guess, there is no appropriate jsf2-taglibrary only the old taglibrary (jsf1) is used in jboss tools.