The organ is exactly like other VSL instruments, not an imitation of using stops on a pipe organ so the screen shot will look exactly like any other VSLinstrument. However every pipe was sampled individually, and many common registrations of pipes were also sampled. So you can use those pre-existing registrations for quick normal useage, or create your own registrations and do anything that could be done on the actual instument.
I've played pipe organs in church and the useage of this particular organ is very practical since the Vienna Instruments and Ensemble interfaces are so convenient to use. If I were going to set up an extremely complex organ stop-switching, I would create the stops as custom presets, in which you can have on one channel dozens of registrations. It is actually easier to do the switching with those than with an actual organ.
What I really like about the Konzerthaus organ is the completeness of sampling all the pipes, and how each one is perfectly looped and ends with the release samples of the actual concert hall. So that means if you use the release samples, the organ is already in that great hall, and if you shut them off, it can be "re-installed" into any other reverb hall.