HitArea Circle

I am trying to set up a cicular movieClip as a hitArea for another, but the circular shape is not detected rather the bounding box of the movieClip. is there any way around it? am i doing something wrong?

TurretRange_mc.hitArea = TurretActive_mc.TurretHitArea;
TurretRange_mc.hitArea (TurretActive_mc.TurretHitArea);

so far i’ve tried these two methods.