Because your posts are only saved whithin the $promo var and not in the $wp_query global var. I recommend you to use get_posts() http://codex.wordpress.org/Template_Tags/get_posts
Because your posts are only saved whithin the $promo var and not in the $wp_query global var. I recommend you to use get_posts() http://codex.wordpress.org/Template_Tags/get_posts