1 / in the publish method, when you're dealing with the attributes, you check if the fromString method exists in the datatype declaration class. The problem is that all datatype classes extend the ezDataType class witch implements the fromString method who does nothing. So if the specific datatype class doesn't have it's own fromString method, the attribute won't be set !
2/ A documentation for the publish options would be helpful.
that's all, beside does little problems, the extension is really useful.