I have been asked by our developers to publish a RH project to a secure Web server using SFTP. The RH publishing dialog box only shows the option of FTP, is there a way it can support SFTP?
Not natively as you have found. On the basis this is the first time I have seen that question posted on any authoring forum, I doubt it would rate as a high priority feature change.
A polite version of "you want it, you do it" seems to be the answer to your developers. I say that as whilst you could purchase a suitable tool, why spend the money when they likely already have something.
See www.grainge.org for RoboHelp and Authoring tips