How to get the system ringtones programmatically in ios?

I am newbie a开发者_开发百科nd now programming an alarm in ios4, and need to get the ringtones programmingly, then, the users set his favorite song for the alarm. However, failed to find such API in ios sdk. Could anyone give me some hints?

There is no public API in the iOS SDK that provides read or write access to the ringtones.

Use AudioServicesPlaySystemSound(xxxx) for using system tones in your Application