iOS How to find the System Sound Volume?

Hi,

I am looking at SystemVolumeDidChangeNotification and the related documentation and also browsing the net.
But I can't find a simple way to get the current value of the SystemVolume.
I cannot believe this information is impossible to get simply, but for some reason I have not been successful.

I also noticed the music application on iPod touch, does exactly what I would like to have, so it must be easy.

Anyone knows the answer?

Thank you for any relevant information.