Thanks for the replies. I tried the scenario again and this time I was able to supress them enough to finish them off with minimal casualties.
I noticed something that may be a bug: if you have soldiers inside a building it becomes transparent and it is very difficult to target the attic. Not just any top floor, it has to be an attic. The only way to target it is when the camera is below the floor. Once I figured this out my supressing fire became a lot more effective and I could finally throw HE at them.
Here is the exact situation, it's from the Vierville battle:
Blue lines are my forces, a platoon of paratroopers. Red are (suspected) enemy positions. One command team in the top floor of the manor and a handfull of guys across the street. Getting into the building was no problem, the part I was having trouble with was moving up to the third floor.
But what is the most effective order to close with and destroy a supressed enemy: quick, fast, hunt or assault?
I meant using satchel charges from pioneers/paratroopers. It would be very usefull in situations like this, where you control the first floor but the enemy is holding the top floors. Or you could blow up a building while retreating, to deny it to the opponent.