Backup on iTunes - fail?

Hey Guys,

I am from Germany so please excuse some grammtical mistakes.

I downloaded the 9.0 Public Beta (for my 5S) but the battery performance was too bad.
So i decided to downgrade back to 8.4.

After the downgrade I connected my iPhone with my Mac to restore my iPhone with the latest backup I made with 8.4.

Well, I had no problems. After 2 minutes my old settings/pictures/etc. were back on it. Just the apps didn't downloaded automatically so I checked out the AppStore and did it on my own. So far no problems.

But now, when I connect it with iTunes, iTunes starts with the "Welcome to your new iPhone" Site.
I can choose between configurate as a new phone or restore with the backup from...

So I restore it again but after connecting it again with iTunes it starts from beginning. So although I already did the restore I cant see the normal page after connecting with iTunes.

So I reset it again and restore it but the problem is still there.

Any ideas???