Include attachments at tag page

after enabling tags & categories for attachments, I want attachments to be displayed at the tag page.

to enable tag & categories I’ve used the following script

function wptp_add_categories_to_attachments() {
	    register_taxonomy_for_object_type( 'category', 'attachment' );
	}
	add_action( 'init' , 'wptp_add_categories_to_attachments' );

	function wptp_add_tags_to_attachments() {
	    register_taxonomy_for_object_type( 'post_tag', 'attachment' );
	}
	add_action( 'init' , 'wptp_add_tags_to_attachments' );

I used the following script to display all custom post types with the requested tag, but I thought attachments are also included.

function post_type_tags_fix($request) {
	    if ( isset($request['tag']) && !isset($request['post_type']) ) {
			$request['post_type'] = 'any';
			//$request['post_type'] = array('post','feature','attachment');
	    }
	    return $request;
	}
	add_filter('request', 'post_type_tags_fix');

When I manually add attachments it doesn’t show any attachments. Somebody knows how to fix this?