Can’t use the new “multitasking” finger-swipes on your iOS 4.3 beta iPad? That’s probably because you updated your iPad in iTunes. You have to restore it in Xcode’s Organizer and click “Use Development Mode” to get the new four and five finger-swipes. You need a valid iOS SDK developer account to do this, it’s not enough to have the iPad’s UDID registered with someone else’s dev account.
Make sure you have the latest Xcode environment installed or you won’t be able to restore your iPad to iOS 4.3 beta. As of today, the latest Xcode build is 10M2508 (Jan. 12th).
Once you restored iOS 4.3 beta using Xcode Organizer, the finger-swipes will be working and you should also see a new gesture-related menu entry in the settings screen of your iPad.