Well I can answer my own question.....
You have to install from the System Center Orchestrator 2019 installer: the Orchestration Console/Web Service from the stand alone installations section . I changed the default ports from 81/82 to 5001/5002.
and then I was able to complete the configuration of the connector in Service Manager 2025:
the Orchestrator Web Service URL is now:
http://SCORCH2025.domain.com:5001/orchestrator2012/Orchestrator.svc/