How to resume iPhone app after a Phone Call

Question

Hi there,

I am creating an iPhone app in which I am providing a call feature with the help of which a user can call place a call on a specified number. I am able achieve the above feature via open URL.

Now after completion of the call I want to resume the execution of app automatically. Although a user can make a fast app switch in iOS 4.0. but I want this to be done automatically.

I have seen the same behavior in "TomTom" app but I am not sure how this app has achieved it.

Thanks

Sandy