Funny enough. The way you get registered changed, since this guy made this video last week.
When choosing an organization, instead of goverment, you have to choose federal agencies, then unmanned aircraft exam. Once you've done that, you will have to click on the message to the right and register in that new webpage to register and schedule the test.
When you create an account on that new web page, you will need your FTN to proceed. Since I don't have one, I can't explain further into details. Sorry.
Update: I did have a FTN. IACRA changed my member number to FTN, so I was able to proceed. Once you enter your new username and password, fill up the blanks with your personal information, you will be sent to a long list of different airman certificafions you can take. Scroll down to the unmanned aircraft and choose general or recurrent.
After that, just follow the questionaire, choose where and when you will take your test and pay for it.