There is a way to turn overlay off with a trick.
First you have to run some other application that users overlay. For instance windows media player and play a videoclip with it. While playing click on pause.
You can use overlay only with one application, so the next video application you start will run without overlay. So if you leave the mediaplayer on pause and then start your webcam software, it will run with overlay off and you can see remote the picture.
It sounds like what he is seeking is a webcam server software. There are many out there, several are free. They will broadcast the webcam to a webpage, which he can connect and see without using RAdmin.
I ran it at my house for a while, but it's sort of quirky.
Basco Shower Enclosures
Millions of people use skype for their phone calls, audio chat etc. and it is very easy to install a web cam. It works quite well also with slower connections. I believe we would all appreciate if r_admin could allow using a webcam also as easily as it is with skype