Topic: How to implement a find_or_create_user if User model uses Devise?

Hi, I'm building a Rails 3.2 app, with two user models - Admin and User - where Admins can create Users using the standard CRUD interface. This works fine, but password and email have to be set in new Users, due to Devise validations.

On a Booking model, Users can be associated using a find_or_create text field on their full name. Currently this works to associate existing users, but is not creating new users. I assume this is because Devise's validation of password and email is failing.

Password is fairly easy to resolve, by automatically setting a password and notifying the user using mailer.

The email issue is more complex. Has anyone else run into an issue like this? What would be a sensible way to solve this, while maintaining the required workflow?

I appreciate that this is a very open ended question, but what I'm really looking for is a sensible and Rails-way approach.

The key considerations are:

1. This is occurring within a nested form, therefore multiple users (mixture of new and existing) can be assigned and created at once.
2. When the form is saved (or before) I need to detect which users are new, and allow the Admin to set email values for these users, so that the User create method will validate.

Opinions and ideas greatly appreciated!