title: iPhone + In App purchase + access alert message buttons
body: <p>I have implemented In App purchase in my application. While testing (with SandBox environment), when I tap on any locked feature, I get alert message from iTunes that "Do you want to buy xxx feature at $xxx ?", with Cancel / Buy buttons.</p>
  
  <p>I want to know that can I access these Cancel / Buy buttons, because I want to implement something based on which button user taps. OR. is there any way achieve like do something if user taps Cancel button and do something else if user taps Buy button.</p>