Not sure what you mean by first act but there were about 4 L missions in total. I can't remember when exactly they became available but the 1st one was available somewhere around 1/4 of the main campaign missions were completed and the last one wasn't available until I unlocked the north Kyrat and about 3/4 through the main campaign game.
I am having this problem too. I haven't been able to do any of the 4 Longinus missions outside of the Campaign given that there is no L on the map. Did you ever find a solution??Originally Posted by Evilgrin1071 Go to original post