how to make those blue radio messages?

[McFinnish]

I'm pretty new on making real missions with the editor, so could anybody tell me how to make those blue radio messages. I've tried from the "triggers", but they don't seem to work   Do I have to make a script or can I do it somehow in the "triggers" thing By the way I need these for my upcoming "Everon - resistance" campaign. You play a team leader who was in duty when the russians attaked into Everon. It will be about 15-20 missions long and will include some tank action. It's about finished; only these blue things and briefnings are missing.

:gunman:

[Komuna]

GREEN RADIO MSG'S: _Unit groupChat "TEXT" - between group m8's
BLUE RADIO MSG'S: _Unit sideChat "TEXT" - between the same side units
WHITE RADIO MSG'S: _Unit globalChat "TEXT" - between everybody
YELLOW RADIO MSG'S: _Unit vehicleChat "TEXT" - between vehicle crew

The same can be aplied to Global/group/...Radio, but first you must edit Description.ext

ex: Player SideRadio "SRT_1"