Download and install the attached file via JFusion's Plugin Manager. Do not try to install it in Joomla's extension manager or else it will fail. Once installed, go to JFusion's configuration page and run the wizard for refbase (it will be a round green icon with an arrow that points right). Enter the source path to the refbase's installation. All the required fields such as database credentials, etc should be filled in. Then go through each settings and read the tooltips and/or descriptions.
Have you had any progress with integrations with Joomla and Wordpress? or the JFusion one is the only one available?
I moved your post to the appropriate thread.
The discussion is still at the same point as it was back then.
We are currently preparing a big surprise ... that will be released in the next weeks. Once we move over, we'll put this integration (and the one with WP) into our roadmap.