I didn't use both 06p and 08p. But from what I've read here, you should upgrade to 08p or 46p anyway because of much longer battery life and better camera.
However I prefer 46p because there I dont have to save each picture from camera before I can make the next (this is a matter of taste only).
You can't recover but you can flash any other available FW if you don't like 08p (06p is available)
I found a maping file at threesearch and made a set of keyboard.gif files that should fit (I don't know unicodes for vietnamese letters so I didn't check each one). I modified the maping file to fit to A1200 (originally it's for A680). It is all in the keybord_viet.rar file
You can use these and follow this guide:
http://www.motorolafans.com/forums/viewtopic.php?t=6285
If you think you can't do that, I can do it for you but you have to wait until I find the time for this, so better try yourself.
With this modification you should have vietnamese characters each time you press the caps key on your keyboard.