How can I get vat_id via SOAP without additional modifications?

Question

I understand that, by default, Magento doesn't expose the vat_id field via SOAP. The accepted answer there is to edit the core/add a module. Unfortunately, I don't have such luxury because I don't have the filesystem access to Magento: I have just the basic SOAP access and I cannot do any modification.

So: how do I retrive the vat_id via SOAP from a Magento ver. 1.9.4.2?

This is what I've tried so far:

$result = $proxy->salesOrderInfo($sessionId, '200000006');
$customer = $proxy->customerCustomerInfo($sessionId, '765');
$addresses =  = $proxy->customerAddressList($sessionId, '765');

foreach $addresses:
  $proxy->customerAddressList($sessionId, '211');

Unfortunately, the vat_id is nowhere to be seen.

What can I do?

Answer 1

This is my solution: copy the vat_idto the taxvat field in the checkout page, then use taxvat from SOAP:

<script>
    jQuery(document).on('change', '#billing\\:vat_id', function() {

        var vat = jQuery(this).val();
        jQuery('#billing\\:taxvat').val(vat);
    });
</script>

(jQuery required)