In the EasySocial backend > Settings > Social >Facebook area, you need to enable the 'Allow Registrations' setting along with the 'Use JFBConnect Buttons' setting. I'm not sure if the 'Allow Registrations' option was necessary previously for our FB buttons to show up, but they didn't appear for me with 2.0RC2 until I enabled it.
If you already have both settings enabled, please let us know more details such as which view in ES you are having problems with, a specific URL on your site, whether its the styling of the buttons or the buttons not being present altogether, etc.
-Melissa