Once again your research is well documented!! I just tested a pre-release of NAS-R3 Enterprise ver. 4.12 build 2659 (on our FTP site for those who wish to test) and this worked over a WAN > NAT on my test server but without selecting the Encryption settings SSL/TLS. I tested with the SSL/TLS settings with Port 22 selection on server and left the Firewall open for all ports just to test and still was not able to get a directory listing (similar to your scenario). So they must be working on this with the new release of 4.12. I have asked engineers to see about the Renew issue as well, so now let's wait and see from version 4.12 from the release notes and if they will have the renew feature as well.