I had the same problem too and I worked around it using turbogears.database.so_to_dict to converto the SO instance to a dict in the controller.
I haven't looked up a way to this "the right way" yet as I'm in a hurry to get a work done. I thought about adding a pre_validator to the Schema validator that automatically converts the SO if neccesary, but as I've said, I haven't looked at it too seriously yet. Alberto
