Please see the change that I made to /httpdocs/components/com_community/templates/jomsocial/layouts/stream/actions.php. At line 110, I added the block of code from our
Common Support Questions
for "How do I add Like / Share buttons to JomSocial feeds".
To test, I created a user with my FB credentials and posted a status to my own feed. It showed properly in my FB feed. Please test and let me know if you have any questions.
-Melissa