All registrations have to go through the panel. But not necessarly 'manually'. It is possible to write a script that would submit the appropiate informaiton to the panel for you, when a person fills out a form on your website. Unfortunatly this is not a very well document option.
Support has said before that it's perfectly accectable to have things posted to the panel in this manner, but they're not going to write your code for you or anything. Also keep in mind that since this is all through your account, you will be responsible even if it was just someone who siged up through your service.
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