Log 55 game hours to unlock this trick.
Press Ignition and Start to remove the cockpit view and play in full screen mode.
There is actually a way to pause the game when you are on a mission. All you need to do is unplug the Steel Battalion Controller and the game will pause and have a warning notice saying that the controller is disconnected. To unpause, plug the Steel Battalion Controller back in the first port and press the Start button to resume the game.
When your rank is Lieutenant Colonel, press ignition + start during a game to remove the HUD.
After logging 100 hours of piloting time, restart your XBox and complete 2082 mode. You can then press Start and Magazine Change during the mission loading screen to gain unlimited fuel and ammo.
At the title screen, move the tuner to the following positions and keep it there for one second each position.
1-9-7-9-0-9-0-6
The numbers above are the positions, like a clock, except this clock starts on the right where the printed numbers start (i.e. 9 o'clock on a normal clock is 0 in the code. 12 o'clock on a normal clock is 4 in the code, etc.)
When you complete the code you will hear a sound effect then you will be able to use all VT's and play any mission on any difficulty in free mission mode.
This code has been tested to work on both SB and Tekki, if it doesn't work try again.
On mission 7 or 17:
Enter the small room to your left as you enter the second floor of the enemy base, after you beat the defending VT inside you will find a VT-sized box with a switch in the back of the room. Inside is the Quasar VT. You'll receive a COM from Argus then the Quasar will be useable from the next mission.