Facebook Comments for Custom Post Types

Hi,

I'm trying to set up FB comments for a custom post type (called 'sales'). It seems that by default WP doesn't allow the use of comments_template() as-is to display comments. I was able to get the standard WP comments template to show using comments_template('sales'), but the FB comments setup doesn't override it as it does with standard pages and posts. How can I set that up? Thanks!