you not going to like this reply but i dont think you can. the data stream is essentially a push to a dataset, so the peices of the array need to be a compelte set of details.
The solve around this is to stream the data to a non profiole enabled dataset, then run something like data distiller against it and create a complete entry with the full object to push into your current dataset. O nly problem here is that getting the data into your active dataset is going to be slow as it runs through distiller first, which most likely means batch