i'd start by turning off icam and trying to get the 2 cameras to show using their native programs, I imagine if one is built into the laptop and one connected that they are both different and using different drivers. I run x3 logitech cams and can raise them all (one at a time) with my logitech software. This would be the first step before looking for them both in icam source, raise them both seperately first if you havn't already. Then turn off the manufacturers programs and the respective cameras/drivers should be found in the drop down menu when setting your camera(s) up. Hope that helps a bit.
Sean