How do I change teams in Xcode 4.4

Seems to be fixed in Xcode 4.4.1 (released yesterday, 7th August 2012).And as Ivan stated correctly: It seems that all profiles from all teams are synced as long as you have the same apple id across all teams.(Tested this by removing all profiles from Xcode in the Organizer and hit "Refresh")

Update:

If you have different apple ids across multiple teams and the login dialog is still missing, you might have saved your credentials in your keychain. See comments #2 and #3 of this answer for a workaround.

There is a strange way to add a new identity (user/pass). If you build and archive and then go to Distribute -> Save for Enterprise, then open the Code Signing Identity list there will be an item marked "Refresh code signing identity" at the end. If you select it you'll be prompted to enter username and password. Hope this helps.

For reference, since I found this page searching for XCode 5.1 - getting XCode to sync new teams on the same Apple ID, click 'View Details' on any teams that are there to see the provisioning profiles for that specific team, then hit the refresh icon. It will also download any new teams added to the ID.