Still haven't got a response to my question with the same title. I have also written to a developer, also no response. Honestly your support sucks.
As for richfaces 4 extended table, absolute mess!! columnClasses not working, Setting a width therefore on the rich:column, does not match header cells with data cells. Horizonal override also causing problems.
I would recommend not using extendeddatatable until a future release.
We are now in the decision making process of re-rolling everything back to the 3 version, since release 4 is very premature. Should not have been released in this state. You can see the developers won't even answer questions, since they must be embarrased what was released.
Really hoping future releases will not be in an alpha state.