Somebody may try this with rellifecam and post result here
Finally found out how to do it.
For future reference, the solution is to run rtmpsuck(supplied with rtmpdump) on a second computer,
while redirecting rtmp stream traffic on the first computer to the second computer by editing the hosts file.
rtmpsuck acts like a "man-in-the-middle" and intercepts/forwards/captures the rtmp stream data.
http://forums.whirlpool.net.au/archive/1520658