i had the same question and was able to add a couple lines to /models/spider.php to add support for custom post types.
right after this line (line 83):
$this->blog_url = get_option( 'home' );
add a line for each post type that looks like this:
$this->post_sql .= " OR {$wpdb->posts}.post_type='customname1'";
$this->post_sql .= " OR {$wpdb->posts}.post_type='customname2'";
hope that helps!