What happens when an Android device is put on hold manually?

Hi,

Does anyone know what happens to an Android AIR app when the user puts the device on hold manually by pressing the power buttton?  Does the app still continue to run in the background, or is it completely paused?

The reason I am asking is I have made an alarm-clock app which fails to trigger ( alarm sound is not heard ) when the device is put on hold, manually ( by pressing the power button ).  However, when the user merely minimizes the app, the alarm does go off just fine.  Any ideas on how to make it so the alarm triggers even when the device is put on hold manually?