Arma 3 Doesn't recognize my fullscreen resolution of 1804x1026 this was the same in Arma 2 however i was able to overcome it by manually changing it in the config file. Upon start of the game Arma 3's config file just rewrites it and thus not allowing me to change it.

Note: WindowedFS isn't an option, despite it find the correct resolution, due to the fact it includes the task bar pushing the display off screen.