Using PC where is the stinger in the "a rock and the hard place" mission in battlefield 3?

Can someone please answer me once and for all HOW DO YOU FIND THE STINGER  IN THE MISSION  "A  ROCK AND THE HARD PLACE" using the PC game in SINGLE player mode . My game was down loaded through ORION and I can't find any files to alter on my PC, surely someone must have a patch or something by know?. I have spent 2 days trying to solve this problem makes a mockery of EA games and Orion for not putting it right sooner puts me off buying any more EA games in future.