North Atlantic Tracks

Hello to all,First excuse me if I'm posting to the wrong forum.I've a little question, I've a flight plan with waypoint over the north atlantic for example 5250N, 5540N. When I fly with those waypoints I've always the ATC who ask me to turn and follow the line in the FS Map. So my question is, how to tell FS : I want to follow my waypoints ! or how to put manual waypoints to the FS Database ???Thank you for your time reading this post.Jeff