EU VAT Number not shown on order edit page

Hey there,
i have the following problem:

When creating an order via the admin order-edit page manually, the plugin doesn’t fill in the meta value of the EU VAT Number Field. As a result, everytime i create an order manually i have to fill out this field again, because otherwise the VAT-number would not be shown on my invoice.

I localized the following code on my class-wcj-eu-vat-number.php starting on line 309, but unfortunately (after wasting about 4 hours..) i wasn’t able to correct this bug…

	/**
	 * add_billing_eu_vat_number_field_to_admin_order_display.
	 */
	function add_billing_eu_vat_number_field_to_admin_order_display( $fields ) {
		$fields[ $this->id ] = array(
			'type'  => 'text',
			'label' => get_option( 'wcj_eu_vat_number_field_label' ),
			'show'  => true,
		);
		return $fields;
	}

Would you please help me with a small code-snippet for my functions.php to insert the eu vat number value automatically when selecting a customer on my order edit page? (i think this is – in general – a plugin-bug which should be considered by your next update ?? )

Thank you very much!
Best regards,
Jay