In Appmethod, it is very easy to set the supported device orientations for the application you are building. Some applications are designed to support all 4 orientations (landscape, portrait, upside down landscape, upside down portrait), while others are designed for only a single orientation, i.e. portrait.
To define and lock your supported orientations, do the following:
1) With your mobile project open, go to Project->Options
2) Select Application
3) Select the Orientation tab
4) Check 'Custom Orientation' and then check the orientations you want to support
5) Click OK and save your project