Hello Christian,

Thank you for writing in, I have synced your purchase with your account. You can view your invoice and add the new domain in your dashboard, by following the steps in the screenshot here http://screencast.com/t/zqxR1UE9P8i

For the API key, one user is only entitled to have 1 API key

Hope this helped. Thank you.

Regards,
Apson Chom