This is keyman keyboard script that is another edited version of Ko Sun Tun's Myanmar3 Keyboard.
As its name, it is based on old Burmese Typewriter. Additionally many of end-user input mistakes are aimed to be fixed in this keyboard. Some bugs may be left to fix. But this is long time ago project of mine and I almost forget how to code it. I just managed to modify the script so that it is compliant with Unicode 5.2. Now I make it public and you gurus may fix it. :P