Directly from the mog station you wont see the ultimatepay option, you have to go to the "add crysta" instead in the separate square enix account management (go to the 4th tab over "square enix account settings" and the third drop-down option will be add Crysta).

I just used the method advised by Timberwolf and it worked (thanks soo much Timber).

For a brief rundown:
Buy an ultimate pay game card (or code from an online retailer such as walmart or offgamers ), in "alternative payment options" in the ultimatepay section choose "use game card" insert the code and it most likely won't work.
THEN call (650) 432 3200 and ask to be transferred to "PlaySpan"
Once there mention you are having problems with using the ultimate game card to add FFXIV Crysta and they will be able to help you out. You will need the email address that your FFXIV account is tied to as well as the ultimate pay game card code to give to them and they will process it for you.
LASTLY after they added the Crysta for you go back to the Mog Station and process your subscription payment using Crysta (for 180 day you will need 7794 Crysta, so you'll need to have bought $78 or more worth of game cards to convert over)