In a nutshell: we need the ability to set the default connecting region as part of the configuration for a S3 Login Session.
We are connecting to an S3 clone service (like dreamhost's S3 clone). Our clone service has different region names from the standard AWS s3. On the WinSCP, S3 login page, when we click login, we receive the error: "The autorization header is malformed; the region 'us-east-1' is wrong; expecting '<our providers region name>'.
Steps to Replicate (with WinSCP v5.13.1):
1) Turn on session logging
2) Connect to the regular AWS S3 service
3) search the session log for the line (near the top of the file): "S3: Default region: us-east-1"
Expose the S3 Region variable so we may configure it from the Session Creation screen. Thanks!