Replace wordpress comments with facebook commenting system

If i am not mistaken this plugin should allow me to replace the standard wordpress commenting system and use facebook instead? I was having trouble getting it setup. i did create the facebook app and activated it though i can seem to get the facebook comment system working. i have another plugin i am using at the moment but it doesnt seem to work 100% either. i am starting to think i don't have the facebook app setup correctly. I could use some help with that please.