It's working fine in CVS (which targets AS 4.2/JSF 1.2) in the itext example for me.
Yep, you're right, copying everything from that example sorted out the issue.
It would be fantastic if there was a list of features in Seam 1.2.1.GA that don't work as-is on 4.2.0..
Looking forward to v1.3!
I think the line is that we support using Seam 1.2.1.GA on AS 4.0.5.GA and 1.3 on AS 4.2.0 really - I doubt you'll get more specific than that!