I've done this in the past, but not with tomahawk dataTable. So perhaps this might not help, but then again, maybe it does.
I used myFaces dataTable. And I just sorted the List on the backing bean. So in the header of the column I have 2 commands (little up and down arrows) that call a sortXXXAscending or sortXXXDescending method on the backing bean. Then this method just uses the Collections.sort method to sort the actual List containing the data.