Full disclosure - I work for Eagle Eye Networks
The Eagle Eye VMS was originally designed to be used instead of DVRs. However, many customers have asked us if it's possible to work in conjunction with DVRs or NVRs or other VMS systems. In some cases we can do this, but not in all cases.
This works when we can get two streams from the cameras, a low resolution MJPEG stream and a high resolution H.264 stream. We manage these streams separately - the low res is called preview and typically goes to the cloud in real time. The high res is generally stored locally until bandwidth is available to send it to the cloud. (these are default settings but can be adjusted)
When we are set up with a DVR or other recorder the limitations are generally on the cameras. Hikvision has several lines of cameras and their lower line doesn't work in this configuration, but there are many Hikvision cameras that do work this way. (we take the video feed from the cameras, not the recorder.)
I'm sorry this isn't working, and without knowing your company name I can't look up the specifics, but if you would like to talk to me please feel free to call our main number (+1-512-473-0500) and ask for me. I will be glad to assign one of our top people to look into this and see if we can make it work.