casualx

Found the solution here:
http://wordpress.org/support/topic/154300?replies=11

$total = "your custom query goes here, but without LIMIT and OFFSET, so the total number of posts that match the query can be counted";

$totalposts = $wpdb->get_results($total, OBJECT);

$ppp = intval(get_query_var('posts_per_page'));

$wp_query->found_posts = count($totalposts);

$wp_query->max_num_pages = ceil($wp_query->found_posts / $ppp);

$on_page = intval(get_query_var('paged'));	

if($on_page == 0){ $on_page = 1; }		

$offset = ($on_page-1) * $ppp;

$wp_query->request = "your query again, but with the LIMIT and OFFSET as follows: LIMIT $ppp OFFSET $offset";

$pageposts = $wpdb->get_results($wp_query->request, OBJECT);