you can change the mission.sqm to alter the side of a unit, change this line side="EAST"; to side="West";
class Item0
{
position[]={9558.214844,23.150715,4694.548828};
azimut=121.603722;
special="FLY";
id=1;
side="EAST";
vehicle="Su25";
leader=1;
skill=0.600000;
markers[]={};
};