iCamSource requires a USB/Built-in webcam or an IP camera that outputs MJPEG formatted data. If your camera doesn't meet those requirement, then iCamSource won't be able to capture video directly from your camera.
However, there is a workaround in this case. It's not very elegant, but it does work. There are several programs available that turn any area of your desktop or a window into a virtual webcam that will show up in the iCamSource Video Source list. If you search for "virtual webcam", you'll find a bunch. I've personally tried a program called ManyCam, and it worked fine for me. If video from your cameras shows up on your computer, then you can use this "Virtual Webcam" program to turn the webcam viewer window into a virtual webcam that shows up in iCamSource's Video Source drop-down list.