Call Register Form in template file using php

Great Plugin!
Im using in my ecommerce site with wp e-commerce.
I want to add in my checkout page, your Register form using php and not shortcode.

This:
<?php wp_login_form( $args ); ?>

echo the standard wordpress form, but i want use the content in register-form.php.

Thansk so much

http://wordpress.org/extend/plugins/theme-my-login/