Hook to Add Your Keys to Product Array

//Add Your Own Keys to the $product array
//This should go in your functions.php file
add_filter('foxyshop_setup_product_info', 'my_product_setup', 10, 2);
function my_product_setup($product_array, $product_id) {

    //Do as many of these as you want
    $product_array['my_custom_field'] = get_post_meta($product_id, 'my_custom_field', 1);

    //Always return the new, complete array
    return $product_array;
}