I am having a similar problem. Webservice is being correctly generated in SOAPUI and in POSTMAN, unfortunately it is not happening the same in UIPATH.
If I use the activity SOAP Request the generated service is wrong. There should be an importing parametar call id_string instead, the parameter name is the name of the webservice with one 1 at the end.
As soon as I click on Invoke I get the following error:
In SOAPUI looks like this:
I found a possible solution by using libraries.
Unfortunately it doesn’t work. The service is “correctly” generated (maybe not), but as soon as I try to publish the library I get an error.
Was anyone able to connect to SAP using SOAP webservices?