Well, I don't believe that there are any BlackBerry devices that support that.
On my regular cell phones, the only time I have "heard a beep" is when the call was lost due to a network issue, but not when the other person hangs up.
Have you tried....
"Can you hear me now?" If nobody answers you...they hung up!
Seriously though...when I still had CellOne I got a tone on my phone when the call disconnected, no matter why. Never really noticed that the BB doesn't do that.