Lets add this as a main answer instead of a reply to an answer.
Heya,
Try adding a leaderboard and/or an achievement to your GameCenter even if you don't use em in your game. I was working with Unity3D and that made a difference on one of my test accounts, it suddenly gor a teamPlayerID after i added a leaderboard and an achievement. Before that i was also getting "Unavailable Player Identification".
Bradakan
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