Well, I do know that register.php, login.php, and profile.php are referenced to /wp-admin/wp-admin.css and that they haven't any template, but how can you implement a login page like this one?;
It is totally integrated with the custom theme, including header, sidebar and footer. How can you add a register.php, login.php, and profile.php template?
I tried this plugin but it messed all the 2.2 installation;