Comments facebook does not appear with "www"

On my site http://amsdarquitetura.com.br, I implemented the facebook comments.

Access the link http://amsdarquitetura.com.br/Project/Details?ProjectID=182 click on comments and leave a comment.

By accessing http://www.amsdarquitetura.com.br/Project/Details?ProjectID=182 and attempting to view the comment, 开发者_如何学Pythonit is not displayed.

The address is different from the address. So facebook displays different comments.

How can I get these addresses are recognized as the same: Facebook settings are as follows:

Site URL: http://amsdarquitetura.com.br/ Site Domain: amsdarquitetura.com.br

Add a og:url meta tag to tell Facebook that the two URLs are actually the same page: http://developers.facebook.com/docs/opengraph/

If you get traffic from search engines too and care about SEO, adding a 301 redirect from the www page to the non-www page is preferable since it tells both Google and Facebook that the two pages are the same, though it's slightly more work than adding the meta tag: http://www.seomoz.org/learn-seo/redirection