Custom Variable Product Type

Hello,

I’m trying to extend WC_Product_Variable to create my own variable product type but am having trouble. I can show attributes on the custom product type but it doesn’t show the checkbox to “Use for Variations”. Looking at the WooCommerce code, it specifically has static a class show_if_variable which, while my product type is variable it’s not specifically called “variable”. Is there a resource, tutorial, or do you have any guidance on what I’m doing wrong when creating my own Variable product type? Here’s the code I’m using below:

/* Create new product type class */
function custom_product_types() {
	
	Class Item_Registration_Variable extends \WC_Product_Variable {
		
		public function __construct( $product = 0 ) {
			
			$this->product_type = 'item_registration_variable';
			parent::__construct( $product );
			
		}
		
		public function get_type() {
			return $this->product_type;
		}
		
	}
	
}
add_action( 'init', 'custom_product_types' );

/* Append product type to select */
function append_custom_product_types( $product_types ) {
	
	return array_merge( $product_types, array(
		'item_registration_variable' => esc_html__( 'Item Registration' ),
	) );
	
}
add_filter( 'product_type_selector', 'append_custom_product_types' );