While I know it's not generally recommended I have had a chance to test this as I was give a HiLook camera - which I understand are simialar to HiWatch now. The camera is a PTZ-N2404I-DE3, connected to a DS-7608NI-I2-8P. It works just fine. It was recognised as a HikVision camera and is able to be controlled by the NVR including use the PTZ functions.
I was also able to get this NVR to work with a couple of old Foscam cameras. As they are not PoE it is necessary to use external power or a PoE splitter with them. Functions such as PTZ work fine from the NVR with the Foscams, but motion detection etc does not. Basic recording works fine.