Q: Check Device is Silent 
Possible Duplicate:
How to detect iphone is on silent mode 

I made an iPhoneApplication which plays a sound if you shake it. My Problem is that many people that use it wonder why it doesnt play a sound if they shake while the device is simply in silent mode. I wanted to solve the problem by displaying an alert if the device is in silent mode. 
My question is: "how can i check wether the device is in silent mode or not?"
