OpenFeint with GameCenter really that easy?

Question

I was reading this: http://www.openfeint.com/ofdeveloper/index.php/kb/article/000089, and it seemed to make out that the implementation of GameCenter with OpenFeint was as simple as adding one plist to the project (after setting up achievements / leaderboards). But is this really the case? I've just implemented this in my project now and can't see any signs of it working. Nor can I see the app in the GameCenter app.

Could it be because I'm writing a universal iPhone / iPad app? Even though the iPhone app is on iOS 4.1?

Can anyone help me out here??

Thanks

James