Victor,
Unfortunately, there's not a real good solution for this. From our understanding, KA Facebook Comments uses the older method that Facebook allows to identify each page on your site. In early March, Facebook updated it's comments box to use a URL to identify each set of comments. We had a method for JFBConnect users to keep old comments intact during the transition, but the previous method to identify each comment box was by creating a unique ID for each block of comments (123, abc, etc). KA Facebook Comments and JFBConnect generated this ID differently, so there's no way to migrate these comments from their system to ours.
Hope that helps explain, and hope it's not too inconvenient for you.
Alex
After using JFB comments I all my old comments and likes gone
