Wordpress flash uploader fix from amember protect

I am using amember protect to protect the whole wordpress folder, however, when I try to use the flash uploader to add images to a post, I get a HTTP error, and in the log it shows a 302 error. It looks like the flash tries to POST to the apache webserver but it doesnt use cookies, so the protect commands in the .htaccess shows as not logged in. (I guess).

This is the error log:
"POST /wp/wp-admin/async-upload.php HTTP/1.1" 302

This fixes it:
RewriteCond %{REQUEST_URI} async-upload.php$
RewriteRule ^(.*)$ - [L]

However, is there a better solution so I dont have to unlock that file to the world?