After e-junkie payment, send a http post to register user automatically?

Question

I have the workflow thought out:

• User pays for something on your site using e-junkie.

• After payment, a http post ( with user email and name gets sent to a wordpress registration script ) and registers that user automatically -- ignores if the email is in database

I think we can use the wp-register.php page for hacking! The problem I am having is having this run automatically.

I already have the option in e-junkie to send an http post after payment with (POST variables to use) automatically -- but now I am not sure how to do the WordPress registration part (automatically)

Post variables from e-junkie:

payer_email Buyer's email address
first_name Buyer's first name
last_name Buyer's last name

Thanks in advance!!

EDIT:

So, here is some code I came up with -- It works, but now I need it to send the username and password it generated to that email address automatically ?? Also the first and last name isn't recording ?? Thanks!!

require('wordpress/wp-blog-header.php');

$user_email = trim(isset($_POST['payer_email']) ? $_POST['payer_email'] : "");
$user_name = trim(isset($_POST['first_name']) ? $_POST['first_name'] : "");

$user_id = username_exists( $user_name );
if ( !$user_id ) {
    $random_password = wp_generate_password( 12, false );
    $user_id = wp_create_user( $user_name, $random_password, $user_email );
} else {
    $random_password = __('User already exists.  Password inherited.');
}

Answer 1

How about using wp_create_user() and then add_user_meta()? Between those two, you should be able to store all the data you get back, and even store it in fields wordpress uses natively.