Hi!
There is no registration number for AD2. I was having the same problem as many of you.
Just go to the XLN website and click on Register Serial Number.
Put in your serial number and if you bought the Platinum it will ask you to select your three AdPac Drum Kits, then your Beat Pacs and then the instruments.
Of course if you bought the next level down it will allow you one of each.
I would advise any of you that can to go ahead and upgrade to Platinum. This is giving me the drum box I wanted in Standalone mode, except with far better sounds than any hardware drum box.
Also you can program your own beats if you wish.
This is by far the greatest upgrade I have ever seen or used.
Tom