Unable to get UniWebView any Callbacks in Android Device.

Hi i am srikanth. we are using UniWebView plugin in our projects for payment related things,It is very nice, we struck at one place that when my web page loaded with payment URl and once the process is completed either success/failure i want to get the call back from webpage so that i can destroy webpage and need to show my custom popups ,In the unity Editor it is working fine i am able to get "OnPageFinished" call back but when i make a build and run in android device i am not getting any callbacks.please help me where i missed the code.i have to submit this build very soon to my client.Expecting response.