How to get Order information of orders generated through subscriptions using xml api

We are trying to get orders generated by a subscription in IS.

$app->dsFind('Job', 1, 0, 'JobRecurringId', $subscription_id, $returnFields);

However this always returns empty, even though we can see the order being generated in IS.

Context: We are trying to use Paypal for subscriptions in IS. So we have an Action set that adds subscription to a contact when someone gets a specific Tag. We are tagging the contact on our end using Paypal IPN.