I think since every second post is about the pings, we need to put that into perspective.
Firstly its very clever and definitely a line of enquiring worth persuing, however it must still be treated with caution, there are some assumptions made just the same as in any other theory.
Firstly the ping is literally just that a ping, it has no identifiable data with it. Its purpose is purely to check a devices readiness it is not limited to just aircraft satcom systems.
The assumptions that have been made in this particular case is that MH370 satcom unit has pinged one hour after its last transmission or acars shutdown and that MH370 was in fact the unidentified military radar target in the malacca strait at the time of the ping. If the assumptions are correct then we listen out for each hourly ping. If on the other hand the assumptions are not for example the ping came from another source say SQ68 bound for Barcelona, then that line of enquiry ends right there.
According to an Inmarsat official quoted by CNN, these handshakes contain a unique code verifying the identity of the aircraft. Indeed, the whole purpose of the handshake is to verify whether the specific aircraft's system is still responding, so what you are proposing makes no sense.
Help from above: Satellite signals can confirm a plane's identity - CNN.com