So the way people have done it so far is by using game cards and adding them to your account, since the way a game card works, once it is registered that time is added to your account and thus you recieve the rewards. I believe the GC are only sold in JP atm and people were using 3-4 of them and by adding them to their account, they recieved 90+ days.
Since we cant do game cards in us yet, and most of us have the free days till the 30th, we just have to wait.