I've had that happen too me on numerous occasions and similar missions. A couple times I ended up just blasting away at each building(which worked). Another time I paused the game and walked away, then continued later(which worked).
If you want to see "PIN POINT sniper like artillery" you should play Theater of War: Battle for Caen. Since you gave ToW2Africa a try you should think about getting the Demo for ToW2Kursk,
http://www.battlefront.com/index.php...571&Itemid=318
I like it more than ToW2Africa. I know a few facts about WW2 but not enough to get in a argument with a knowledgeable person. I do know that I love playing WW2 RTS games and even with all their flaws the ToW games are some of the most enjoyable WW2 RTS Games out there and can be purchased at insane prices from time to time.