You could do this:
- On the form where you have the file saved in an attachment field, build a filter which saves the attachment into a folder on your server (by using a "Run Process"-action with "PERFORM-ACTION-SAVE-ATTACHMENT")
- The second action in that filter then does another "Run Process" and this time you run a command-line SFTP-client (or possibly SCP? But I think SCP is different than SFTP, so maybe SCP is not what you want) and you give it the source-file and destination as parameters. (Since the Run Process action can't prompt you for a username/password, you'll have to set up SSH-keys beforehand so that the transfer can go through without user-interaction)
Hope this helps
Please could you provide details for the second step along with a sample.
To your point, years ago we switched an HR automation process from ftp to scp using pscp. I am pretty sure the driver to switch was we were asked to change the integration to sftp and it was easier/better to go with scp instead (our accounts on the AIX side did need to be changes a little to allow it).
We are using a .vbs script that Remedy passed arguments to in the Run Process (actually we are performing the Process in a Set Fields because we want an error if it fails). In our case were are creating a .csv file of Remedy and static data so we wrapped it all up in a script. If you are simply passing data you could probably just call pscp from the Run Process directly.
And now that I have typed that up and re-read your question, you didn't specifically state you are sending the file to a UNIX variant OS. If you are sending it to a system off-network or a Windows sever what I typed really doesn't apply. So, if you still need to use sftp I would do the same as I described above, create a script (I would use PowerShell these days) and call a Windows sftp client from within that script.