As an extension of setting up a SOAP client and server, the server connection can be tested with an external tool called SOAP UI.
* Step one: download SOAP UI and open application
* Step two: start a new SOAP project (via File) with project name and importantly the initial WSDL file. Download the file first OR simply enter the url, this part of the UI is confusing.
* Step three: Notice the Navigator panel on the left with all WSDL logic interpreted.
* Double click UnitConverterBinding > Convert > Request1
* A new panel opens with on the left the correct XML body, the question marks should be replaced with actual dummy content (weight, fromUnit, toUnit).
* Click the green button on the top-left to submit the request to the specified endpount url. In the right-side panel the XML response appears.