Thanks for the details and link to your previous posts. I was able to scour around and find a bug report in Facebook's system about the "Post as.." functionality missing in the comments area of websites:
developers.facebook.com/support/bugs/946232449543022/
I'd recommend posting to that comment that you are experiencing the same problem. Hopefully, it's just a bug that Facebook will correct soon. Sometimes, 'bugs' become permanent.. so the most important thing is to let them know it's being used by as many people as possible.
I hope that helps give you a direction, but unfortunately, there's nothing within JFBConnect we could do to fix this.
Thanks,
Alex