Apple doesn't allow the issuing of serials etc for Appstore games. Your purchase is registered to your iTunes account, so you don't really need to register it to the site.
Thanks for the super quick reply (best support prize) but
1) in this way i can't be in the Battle Academy rankings?
2) i joust recived by mail the beta of BA 2.0 that ask for my serial to be played!
The open beta is for PC only at the moment (Mac coming soon). We cannot do open iPad betas, as the process requires getting people to sign up and get their UDIDs and so on. Sorry if the mail wasn't clear on the fact it was for the desktop versions.
Rankings are definitely on our radar, and we would link to your account even without a serial, as we do when you login to the multiplayer server now. So iPad players would definitely be on the ladder .