playing local sound file

I need to play an mp3 file in my AIR app. But I won't necessarily know the path to the file because I need to use things like the storage directory. So, would I have to do something like this to get that done:

var file:File = File.applicationStorageDirectory.resolvePath("path/to/mp3");
var urlRequest:URLRequest = new URLRequest(file.nativePath);

and then load the sound from that? Or is there some way that AIR has provided to skip the first step?

Thanks!
Kyle