Ok, but you should ask that at some AS2 forum. This is not really a WinSCP question. Your question originally sounded like you ask just for WinSCP configuration. But now it looks like you know you have to setup something on AS2 side first. We cannot help you with that.

Hi Martin,
I know this software, but I'm looking for a free connector.
Thanks for help
ilario

Would this help?
https://aayutechnologies.com/docs/product/as2-gateway/sftp-integration/

Hello,
it is possible configure an AS2 connection with WinSCP? (Applicability Statement 2 HTTP-based protocol used to transmit messages in EDI systems).
I'm searching an alternative for RSSBus software.
Follow indication found here:
https://www.comparitech.com/net-admin/best-as2-software/
seems would be possible. If yes, where I can found config info?
Many thanks for help.
Ilario