I don't see any issue. However if you want the classes to apply to different rows the list has to be comma-separated; space-separated classes get applied together. What version of RichFaces are you using?
Thanks Michal for your reply!
Hm, now it's working for me, too. But it definitely wasn't working when I posted the question. I don't know what I did wrong but the given example above works now. And the hint with comma vs. space separated list is correct.
For the records: I'm using RichFaces 4.5.1.Final.