In digital, The sound is sent using the same cable as the video source.
In analog you must have a sound device connected to the camera as well or there will not be any at all. Usually this is done either through a doggle that uses RCA ports for sound and video or by using an S-video cable for the connections. This is dependent on what capturing software program you use as well. As you have shown that it works in certain software but not other then you should try to connect the sound as a seperate signal and see if you pick it up then.

I had Studio 7,8,9 and all of them did the same thing on analog cameras, but worked great with digital cameras....also there is a note on the old programs that mentioned for analog cameras only or for digital cameras only. I always had to be careful about getting the wrong version