If you connect the camera to the network, I believe that you'll still be able to control the PTZ through the NVR. I have never tried this myself though (so let us know if I'm right), but at least there's no obvious reason for it to be impossible as long as the NVR is aware of what type of camera it is connected to.
On the other hand, when you add something purely as an RTSP stream (e.g. as you add the NVR's video stream to Camect), PTZ control is not possible as the RTSP protocol does not include any way to control PTZ.