Drupal and apache rewrites

Question

I'm just migrating a site that has a proxy pass in the vhost config like the following.

ProxyPass /n/ http://xxx.xxx.xxx.xx:80/n/
ProxyPassReverse /n/ http://xxx.xxx.xxx.xx:80/n/

I need to replicate that in the drupal .htaccess file as I don't have direct access to the hosting as we're using a fully managed drupal solution. I have tried the following but it does not work, when I navigate to the drupal site /n I just get a 404.

RewriteRule /n/?$ http://xxx.xxx.xxx.xx:80/n/ [P]