Install the game with a monitor thats only 1600x900 max resolution
Fully load the game
exit the game.
Exchange the monitor with a 22" LED tv thats connected with a standard HDMI cable.
Relaunch arma 3 in development mode
-Notice that the game is loaded but off center and large black border to fill up the unused space outside of 1600x900
go into the video settings and select 1920x1080 and it will notice that the size does not change and there will still be a large black border. It will remain in 1600x900 but it will have a 1920x1080 resolution in the size of 1600x900.