Hi,
According to specifications the cameras support the ONVIF standard so you should find them when adding them to NCS using the tab for ONVIF Source and then click on Browse. To work properly in the long run you should set all cameras to use static IP.
How did you find three of the cameras?
Do you have a camera connected to NCS and working?
Login to the camera and make sure that ONVIF is enabled.
More info here My IP camera support ONVIF but it do not show up in Netcam Studio