Men Of War: Red Tide mission question

[Sneaksie]

Actually, defending this building is not optional, its required.
Do you have a savegame when this glitch occurs?

[imran764]

i have also cleared this round in first attempt.
lay mines and atleast one of your men should be on the roof of the building.
well i didnt prepare myself well so i lost every men of mine just three were left and i finished the stage.
good luck