The Web Service Connection screenshot you have posted would be used if you are wanting to send outbound message traffic to an IHE web service. If you would like to receive HL7 messages from another system you would setup the channel source node (green node) to listen on an HTTP or HTTPS listener. Here is a KB article on how to setup the source node.
How to accept HTTPS connections.
This connection type will produce XML with your content (HL7) embedded in the content node. Here is a KB article on how you can access the content.
How to access the payload of an HTTP message.