This component exists in mojarra but it is missing on facelets tlddoc. After
asking about that to Ed Burns on JSFDays, it was confirmed this component should
be part of the spec, but since there is no documentation about that, myfaces
can't implement it until the documentation could be published. I'm keeping an
eye on mojarra javadoc throught its nightly builds.
This one definitively should be included on jsf 2.0 rev a.