Probably finally fixed addon communication channel, now by more reliable way. Again, thanks to Lotert for supplying additional information and sample script.
This should also eliminate the temporary ability to understand the other faction.
Also I've done some research on new transport system introduced with Cataclysm, which allows us to control the movement of transports by server itself. This should be good base for future development of Strand of the Ancients battleground and Ring of Valor arena, as well, as some encounters with dynamic transports like elevators and so.