First, I guess you mentioned thing is not SSH connection, it is HTTPS, right?
Then, you had better read this KB article: viewtopic.php?f=5&t=142
, maybe it can help you solve your problem.
You can also have a test on our demo server(our server installed signed certificate): https://demo.wftpserver.com
(USER: demo-user, PASS: demo-user), you can upload something into directory "upload_demo"