How Can Get the actual Pre Shared Key to Application instead of “*” in Android

I am trying to access the pre shered key to my application using WifiConfiguration class provided by Android. The "AccessPoint..getConfig().preSharedKey" returns only "*" if key is present and null if the key is absent.I need the actual the pre shared key. How do i obtain it ?
Is there any other method that I can use to get the key ?(Can I modify WifiConfiguration class?)