Lightstreamer requires that data is split into distinct fields, so that the Server can easily distinguish changing fields, to be transmitted, from unchanged fields, not to be transmitted.
If your objects have a complex structure and you can't represent them as a collection of fields, then you can sacrifice transmission efficiency and serialize your objects in whichever way into a single String field. However, deserialization must be performed by custom code on the client side (JSON helps this very much).
This can be done by using a NonVisualTable and implementing the "onItemUpdate" event handler so as to get the data, deserialize it and manage any display actions (and indeed I suppose that, with complex objects, our support for VisualTables made up of push cells would also not be useful).