Install the most recent JBoss AS tools.
- Go to Help > Install New Software.
- Set Work with to http://download.jboss.org/jbosstools/updates/stable/helios/
- In the results, select Web and Java EE development.
- Next, etc, Finish.
This will get you the JBoss-provided server plugins, including the one supporting 6.0, along with several easing JSF development plugins, such as EL autocompletion.
You only need to ensure that you’re using Eclipse Helios SR1 (at least, the most recent WTP version). The initial Helios version had some vague problems with JBoss AS Tools.