panorama on "[Plugin: WooCommerce - excelling eCommerce] Pre-populating the shipping address with Zip/Postalcode"

Hi,

I would like to pre-populate the zip code in the SHIPPING address form on the checkout page with a zip code a customer entered on the product page (to check if shipping is available in their area).

Does anyone know what file(s) I should be looking at? I can't find which one.

Thanks,
Glenn

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