Hi,
This is happening due to the fact that these are ONVIF cameras. I wouldn't say your stuck because they were not purchased from us, as we sell ONVIF cameras as well.
The reason this is not working is because when using the ONVIF protocol not all information is transferred between camera and NVR. Unfortunately, this happens mainly with the motion settings.
I truly wish there was more we could do, but if certain functions of your cameras are not passing through to the NVR then that is just the way it is due to the ONVIF protocol. Honestly, this is to be expected from ONVIF cameras, even the ones we sell. The motion must be set in the camera itself, however we can still manipulate the motion settings enough to enable email.
Let me know if there is anything else we can do for you. Thanks.