i have done some ground attack ME's and i know that you have to use the right aircraft for the job. in the dcs ME model the fighter jet has to detect the ground threat with it's radar to attack the ground target. when you set an aa gun on the me map(anywhere)use a su-25 or a-10,make sure that their way points go thru the aa guns area of detection. when you make their way points make sure you set them at FLY OVER POINT(in other words the attack way point should go right over the aa gun),so the jet has to fly thru that way point to get a detection from the ground target and when the fighter jet detects the ground threat it will move out for the area and set up it's attack run.