Good Question!
Here's your answer:
The referral program only works if the referred player is not already subscribed, so if I understand your situation right, it wouldn't work for you, unfortunately. It sounds like your friend is already a customer.
However, you can refer new friends with the referal program and as long as they have upgraded to a full version from trial sometime after your referral, and start a paid subscription you'll get credit.
Now here's the tricky part... you want to pay for your friend's subscription (and probably the upgrade too.) Here's how we suggest it be done:
1. Refer your friend, and see if they like the game.
2. If they choose to keep playing, you can visit our store at
http://store.turbine.com and purchase a digital download key for theme to upgrade with.
3. There are two ways you can pay for another player's subscription. A: Visit our partner site at
www.paybycash.com/ddo and purchase a game time code for them to use during their upgrade process. This will allow them to upgrade and grant you referral credit.
or B: Have your friend use his or her credit card during the upgrade process (they will not be charged for the first 30 days.) and then immediately call our Account Support department at 781-407-4020 and ask to make a "One Time Payment" on a friends account. You will need your friend's account username, and your own credit card. This will not apply your payment information to the friends account, but process a one time payment.
Remember, never share your password or credit card information with another player, and never offer to put your credit card on another players account via the website! Doing so can result in non-refundable charges and the account becoming banned. The above two methods are the only way to properly receive a referral credit when paying for a friends account.
Hope this helps!
-Quarion