Take out the machine guns on the tanks first w/lancers and the Edelweiss. Probably will take 2-3 turns depending on level. Also you gotta have an engineer around to fix the Edelweiss and restock your lancers.
In the meantime, two things: 1) Send a scout to blow down the blue walls using grenades so that the tank will have to shoot them and expose the coolers. 2) Get someone always ready to climb up the tank and drop a grenade on the coolers when exposed. Make sure you get the one that faces south first before the crazy indestructable chick shows up. Reason: once in place, she will always be next to that side of the tank and she'll kill you every time if you get close to that side. As I recall, she won't go after the Edelweiss so protect your troops first. You can try to use lancers and the Edelweiss to shoot the coolers but as I recall, they'll take 3 shots to blow up. Easier to have one of your troops drop a grenade in it. One grenade, it's done.
When she does show up with her reinforcements, you'll need a shocktrooper or two (or sniper) to kill her troops. They'll be coming in from the upper right of the map. So put those two near the base in the lower right of the map so you can pick them off when they arrive from above on the cliff. Or you can just shell them with your tank as they get closer. I did a combo of both sniper and mortars to kill the lackeys.
Don't worry about guys going down, save them as you go and order reinforcements. You should have at least a couple lancers and the Edelweiss around to kill what's left of the tank. You'll need to take a stand there after you get all of the coolers destroyed. I'm sure there's a better way but this was how I did it on the 3rd time around after getting smoked by the indestructable gal with the shield and lance the first time. The second time I ran out of "space" and my base was overrun because I didn't get to the last cooler until the tank was right on top of my base (didn't blow enough walls down). I was one shell/CP short
