Ultimate Facebook isn't overriding wordpress comments

Hi! I've checked the option to override wordpress discussion settings in Ultimate Facebook, but it didn't work. I already read the topic https://premium.wpmudev.org/forums/topic/ultimate-facebook-plugin-comment-override-not-working but I wish I could have another solution than installing one more plugin.

All I want is to have that facebook comments box on my site, like 9gag or many other sites; I don't want the wp comments box.

Thanks!