problem SOLVED!
Pluggin: Facebook Comments for WordPress (actuuly this one is the TOP RATED one. With 250,000+ downloads, so you shoulkd consider to useTHIS ONE with wordpress).
Okay.
THE ISSUE (which i, and most ppl) had: After the installation, the plugin only showed "LIKE" button an the end of the cage, but no "comments" section appears.
THE SOLUTION: Install plugin - go throght "normal" settup proccess, (where you should provide the pluggin with your ID and app secret ID).
Then, just go to the Settings menu of the plugin (you are already at this menu anyway), and there, scroll down the page, and check the box "Include Facebook JavaScript SDK"
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Thats it.
Yeah yeah, i know, this is by far the stupidest glitch ever. Plus, the box itself have a comment "(This should be checked unless you've manually included the SDK elsewhere)"
total FACEPALM
Why doesn't developers "enable" that check-box by default if they tell so by them-selfs - i got no F idea. Never-mind.
Worls for me well. At least it words with "SHOUTBOX"
Check \ test page: http://imba-shopping.com/3-post-test/