Single Sign On in Moodle with external login form

I'm developing a moodle site where I have to use an external service for authenticating users. This SSO service should be the only form of authentication. The provider of the external service requires me to do use their login form on their server so I have to disable the moodle login form. I have looked at the various authentication plugins but none of them seems to do exactly what I need them to do. Thus far I think this is what I'm going to do: 1. Change the login/index.php file so it does nothing but redirect the user to the external login form. 2. The SSO service heads back to a new page on my Moodle server that confirms the credentials supplied. 3. All relevant user data is collected from a SOAP webservice connected to the SSO service. 4. If the (unique) username provided by the SSO service exists in the mdl_users table the row is updated with the relevant user data. 5. If the username does not exist a new user is generated automatically The user is then logged in to the Moodle site and headed to their front page. This is my first time working with Moodle so I have a few questions: 1. How can I create a new user automatically? Is it enough just to add a new entry to mdl_users? 1. How do I sign a user in? 1. Can I make this sort of functionality as an authentication plugin or do I need to make a hack in the login/index.php file? 1. How do I disable the no longer needed parts of Moodle's own user management (i.e. password reset, user info fields that are collected from the SOAP service etc.)? I really hope you can help me :)