FB礼品请求不显示为推送通知（Unity 3d Facebook SDK）

I am working on a game in Unity3D and I want to integrate facebook with it. I want to be able to send a gift request for my app to a friend, but the thing is they appear in user's notification panel of Facebook but they don't appear in Notification Panel of my game. I want them to see a notification, like in Candy Crush(when someone receives a request in Candy Crush this also appears in the notification bar as push notification). I am working on a game in Unity3D and I want to