DrByte:
If you're registering the customer, why not just use the regular create-account page? That will register them and send them an email welcoming them to the site.
As for disabling registration, you could rename the create_account page by renaming /includes/modules/pages/create_account to another name; then rename your tpl_create_account_default.php template file similarly, and finally update the /includes/filenames.php to give a new name to the value of FILENAME_CREATE_ACCOUNT (the value on the right-side of that definition). You might want to also remove the call to the create_account module from inside your tpl_login_default.php template file so that the login page never shows the create-account option.
Well it isn't so much them being able to use the page as it is that if you click the login button on the external login page it redirects to the login/create account page (for error handling) so anybody is able to find the page and create an account.
It would just be easier to have it redirect elsewhere if there is no login information or an error but from what I researched you can not change where it redirects so the next option is to remove the registration option all together or as you explained hide it from the normal user.
bigbadboy:
Or you could use the Add customers from Admin mod.
Thanks. I will give that a try as I must have overlooked it in my searches earlier.