Executing a Finite-Length Task in the Background

Is there a way in Corona SDK (Pro) to declare a function/task as requiring extra time (a few seconds) before the app is suspended by the system?

The Apple API are:

class: application

method: beginBackgroundTaskWithExpirationHandler

Background information for requiring this: I am looking for a friendly way to implement audio fade out upon the user pressing the Home button.  My apps audio seem to come to sudden stop no matter if I implement s 1.5 seconds fade out or not.

Thanks in advance for your replies.