Ok Cosmin, I know the mission your'e on. After you arrive in the truck and you take out all the guards, you arrive at a gate. To the right are three buildings. The nearest on to you has the info. when you go in, there is a door to the left, go in there and you'll find some stairs going down. down there is a couple of germans and a book which is the tiger tank manual. its on the table.
I think this is the one where you have to be quick to shoot any guys near the alarm system.. if they do set it off turn it off as quickly as you can or more guys will keep showing up.. check all rooms and you will find some more bonus objectives achieved.. oh yeah, wait until you try to escape the compound.. that part drove me nuts for a while..