I'm not sure if I fully understand your question, but hopefully I can at least clarify some of the queries.
The SCXI-1600 carries out the data acquisition side of things with your SCXI kit and it is used instead of having to connect to SCXI via a PCI DAQ card. In software (MAX) you should be able to see all of the modules within your SCXI system, all of which are fully addressable directly. You don't need to firstly transfer data from the modules to the 1600 and then transfer this to your PC, this i all done seamlessly.
Have you configured the system in MAX yet and are all modules present? If so, try using the test panels by right clicking on the module and see if you can acquire the data. I would then have a go at creating a Task inside MAX, which can then be called from LabVIEW or similar.
Let me know some more about your question and I'll happily help you further.