Okay, I got it finally, and I only lost the one soldier who is outside a tank! I used a strikingly different tactic though. I sent all my tanks way off behind the town (in the opposite direction to the enemy advance) and then laid a bunch of mines and satchel charges inside the town itself. Then I let the enemy roll right into the town. I perched myself on top of the skyscraper with the Dragunov and an RPG and killed all the RPG soldiers at a distance, then took out the BMP's with the RPG. Half the tanks bought it on the mines and satchel charges, then I called my tanks back in to massacre the remaining forces. Nice...