I have made a lot of testing with this problem and here is some code that locks the screen into one position. On loading the app, detect the rotation and rotate back. Also lock the flash position=disable rotate sensor.
Put code inside selfevent load.
var sensors = new Service("Service.Sensor", "ISensor");
fscommand2("FullScreen", true );
var deviceObject:Object = new Device();
Stage.scaleMode = "noScale";
Stage.align = "TL";
Then it's good to make some waiting time for app to gain full screen (without the buttons) and run code:
if(_global.widthh > _global.heighth )
this._rotation = 270;
this._x = 0;
this._y = 230;
There might be multiple errors in that code..