JFBConnect's primary role isn't just social authentication, we offer almost 50 different widgets (Like buttons, comment modules, etc) for the various networks we support, social meta tag support for getting the best preview shown when your content is shared back to a social network and more.
With that said, we don't perform the integration with JomSocial that you're looking for. You can add a Facebook comment box to your articles, but comments there won't show up in the user's JomSocial stream. There are various technical reasons why we don't currently support that. As you probably guessed, our main focus is getting content to and from your site to the social networks.. not between different extensions on your site.
For more options within JomSocial, you'd need to contact their developers who may be able to point you in the right direction.
I hope that helps,
Alex