It looks like there is only a store order details server behavior on the confirm page. In here I can see that the first two values that are being set are:
& ToString(Session.resumeCart_OrderID) & "") & "|" & "" & ToString(Session.SessionID) &
The OrderID that is being referenced should be based on the store order summary server behavior. Since I do not see that on the page you may need to add it to get this variable being set correctly. As you can see the other id is just the session id. So if you can use sessions on your site then this other value should be valid. Try adding in the store order summary server behavior and make sure to set the name of the session variable to resumeCart_OrderID. Check this out and let us know what you experience.