Badger had a few problems with his installation of Arma 2 OA, the problem we had was that we couldn't hear his gun firing (no matter what weapon was picked) and he couldn't hear our weapons. For those with Arma 2 and Arma 2 OA. With the latest version of Arma 2 OA v1.62 as long as you have started/played the original Arma 2 (which is also up-to-date) when you then start Arma 2 OA it should automatically connect the Arma 2 content.
The reason I mention this, on the Insurgency Simulator, we use content from both Arma 2 OA and Arma 2 so if you don't have both products you will miss out on some items (ambient cars, weapons etc). I've added a few more of the Arma 2 Weapons into the loadout on Insurgency Simulator Lingor map as I noticed a few were missing (my personal favourite at the moment is the black G36c rifle with iron sights, mainly for the transparent magazines).