Game Center break Unity game orientation

I'm using Game Center to make leaderboard in game now, but i got a problem: even i set portrait orientation when build in Unity and Xcode, but when i login to Game Center, it change game's orientation to device's orientation. My game set in portrait, so when change to landscape orientation, it break the image and structure in game
I got the same problem when share Twitter, so anyone can fix it ?
Beside that, now i share Twitter with text and image, and it become a problem when i push Home...

Game Center break Unity game orientation