No idea, I would need DEBUG log output when the binding tries to connect to see what is going on.
I would recommend you install ONVIF device manager and see if it detects and reports a snapshot url.
I believe for a camera to call itself ONVIF compatible it is required to support a snapshot.
Since the binding was reporting a RTSP link, you should look at the other thread you already posted in and I replied in, currently the binding does not support RTSP as it is still being worked on as I find spare time.