Most of this code is in the arty wiki just check it out or ask questions if your not sure about anything.
Just execute this on the server and provide the names of your arty battery's to the corresponding(_mymlrsBattery,_myd30Battery).
Code:
// Create the Fire mission templates
_heTemplate = ["IMMEDIATE", "HE", 0, 15];
_illumTemplate = ["IMMEDIATE", “ILLUM”, 10, 15];
// Get pos of the target above sea level.
_targetPos = getPosASL _targetUnit;
// Execute the fire missions.
[_mymlrsBattery, _targetPos, _heTemplate] call BIS_ARTY_F_ExecuteTemplateMission;
[_myd30Battery, _targetPos, _illumTemplate] call BIS_ARTY_F_ExecuteTemplateMission;