Yep, it can be easily saved/loaded to that array, and Ubercart takes care of the saving/loading. In other words, if at one point I do this:
<?php
$order->data['vat_id'] = 'ATU12345678';
?>And the order gets saved, on subsequent loads, I can pull up that value with:
<?php
$vat_id = $order->data['vat_id'];
?>The tricky part will be collecting this from the customer at checkout and displaying it on order screens. For that you need to use the checkout/order pane APIs. You might look into the lead tracker contribution for example code.
Joined: 08/07/2007