In case of asynchronous scenario for the SOAP or HTTP connection &qos=EO or &QualityOfService=ExactlyOnce should be added to the URL in case if it has format like this:
http://<server>:<ABAP-port>/sap/xi/engine?type=entry&version=3.0&Sender.Service=<YourService>&Interface=<YourNamespace>%5E<YourInterface>
XI tricks 