I think wagnerb has discovered a design flaw. I also do not use the VOIPo VM, due to WAF, and I certainly do not expect it to act this way either.

wagnerb, please open a ticket. I too would expect the line to just ring and ring in this scenario, like the phone company does. Or, if I have VM disabled, and the system insists on using it anyway, then it better send me an email or something telling me there is a message!