Just an update for future readers, I was able to get WSDL workflow working with “POST” node and using WSDL request in the “Request Body” section of the node as described here:
Generic Web Service Client seems to have problems as it retrieved 3000 duplicated rows when used for a single request and was not able to parse xmlgregoriancalendar dateTime properly. With Post node I used time format “2020-05-20T00:00:00” and it worked like a charm
