Hack to get it working on nginx without rewrite rules

Add the following code to the bottom of the main php file:

function wp_dlm_request($input) {
	if (!empty($input['name']) && $input['category_name'] == 'download') {
        $_GET['id'] = $input['name'];
        include('download.php');exit;
    }
    return $input;
}
add_filter('request','wp_dlm_request');

It’s ugly but it makes it work without fiddiling with rewrites (or at least it does for me). You might need to change the if if your using different permalinks.