How do I set the postal code?

Hi,

I currently set all my shipping address automatically like this:

// Hook in
	add_filter( 'woocommerce_checkout_fields' , 'custom_override_checkout_fields' );

	// Our hooked in function - $fields is passed via the filter!
	function custom_override_checkout_fields( $fields ) {
$fields['shipping']['shipping_first_name']['default'] = 'Jackie';
	$fields['shipping']['shipping_last_name']['default'] = 'Chan';
	$fields['shipping']['shipping_company']['default'] = 'Company x';
	$fields['shipping']['shipping_address_1']['default'] = 'X Road';
	$fields['shipping']['shipping_address_2']['default'] = '#0X-01';
	$fields['shipping']['shipping_city']['default'] = 'Singapore';
	$fields['shipping']['shipping_postcode']['default'] = '123456';
        return $fields;
}

Prior to the recent woo commerce updates, it runs fine. But after the recent updates, the postal cannot is the only value that I cannot set. I need to set the default postal code. Please asssit

http://wordpress.org/plugins/woocommerce/