Login to SFTP/SSH using AD

Hi!

I want to use SFTP in order to allow remote users to access their content from outside my local network. The problem is, using an AD account to login to SFTP/SSH does not seem to work. I also tried with regular FTP / FTPS, but no luck. Honestly I'd rather use SFTP. Does anybody here know if it is possible in some way to login to SFTP using AD accounts?

I'm on FreeNAS 9.2.1.7-RELEASE-x64.

- Aleksander