From what I was told yesterday about the DDE for the AP. in order to get the DDE you need an AP or A voucher #. I m sure you know this. However, they say it takes 2-3 weeks to get your card. The DDE starts the day you purchase it not the day you activate your AP. In our case we will be leaving before they can get the card to us but we were given a confirmation # and we can get a letter from guest services when we arrive and that will be our card until we get ours in the mail.
I know when I called they said that the 2 options for getting the DDE was to speak to a CM at the DDE phone number or go to Disney.com/passholders and sign in to order it. Im not sure if you can get it in person at the TTC,DTD, or Guest Services. I would think you can but I would call and ask. Im sure someone else probably knows. If you can Im sure they would provide a tempory card or letter of some sort until you receive your regular DDE card.
Hope this helps