If you are confident in c# the WinSCP automation is quite powerful and stable.
If I didn't have to have had to apply so many business rules I would have used your method though, bookmarked it for future reference.
Stan Kulp-439977 (3/13/2014)
jbuchan (3/13/2014)
I have just completed a project on this myself but I hadn't used those components as I didn't know about them at the time.I used WinSCP automation
http://winscp.net/eng/docs/library_install
and Bouncy castle decryption runtime
http://www.bouncycastle.org/csharp/
I then had it all in script tasks
I wrote an article a while back on SFTP using puTTY from a script task.
It works, but I found its reliability to be wanting. Popping up a command console in the middle of executing an SSIS package just doesn't seem to work as well as it should. I found it was failing about one time out of ten. That's when I started looking for a replacement and stumbled upon this set of extensions.