Notification when user account is registered

I couldn't find it anywhere, but it seems that you can't actually set a notification (in form of e-mail or just a notification in the Atlassian notification bar) to a project admin if the new customer account is registered.

My project is set that only project admins can invite new customers but I still would like to know if the invitation is still pending or if the user has registered (would be good in the Customers section in the navigation side bar.