What doesn't work with the function: AJ_NETSDK_IPC_PTZControl() on page 21/22?
Or are you not using the SDK functions to retrieve the RTSP stream but some other ready made interface for LabVIEW? Meaning you have no idea how to interface to a DLL?
A few points to consider:
1) The camera may not like a secondary connection, either through the SDK or through generic TCP/IP while it is busy streaming image data to the VLC or whatever interface.
2) Trying to reverse engineer the TCP/IP binary stream protocol is likely going to be cumbersome and difficult to realize as it is usually proprietary. The SDK interface is simple enough to use, except if you lack any and all understanding about C programming. It's not a CIN node either that you will need to configure but a CLN (Call Library Node). CINs are not only legacy technology but on most modern LabVIEW versions simply not supported anymore.
An interesting problem, but none I can help you as I do not have that hardware, and I would expect it to be a bit cumbersome considering above 2 points.