You can certainly add additional content to the order confirmation page. To do that:
1. Go to Manage Fulfillment > Settings > and under General Settings click on Commercial Terms link
2. Look for Order Complete (insert) page and click configure button next to it.
You will then be able to add any additional content to the order confirmation page. If you want to add any redirection, survey form or any clients based scripting in general, you can also do that but make sure to click "Source" button first and verify that the Override default content checkbox is selected