Okay, I don't know a whole lot about iscripts and stuff, but here is what i would try
1. Make its intial ground and air, repeat ground and air, and return to idle scritps look just like the turret's.
2. In the turrets repeat gnd attk script there is a goto offset 26051 command. This takes it to the first line of the initial gnd attck script (just type the # into the offest search box on bottom right) Make the supply deopt's scripts go the the appropriate place with those commands (ie. Supply depots rpt gnd attk script should say goto offest 38886 because that is the first line of the supply depot's intial attk script
)
Confused
I really hope this helps, but as i said i don't know much about this stuff