Share Rails 3 Phusion Passenger Deployment Between HTTP and HTTPS

Question

I have an apache virtual host for port 80 that hosts a rails 3 phusion passenger application. I would like some actions of the application to switch to https (port 443). What is the best way to share one instance of a phusion passenger rails application between two vhosts?

Right now, I have:

<VirtualHost *:80>
    ServerName mycompany.com
    ServerAlias www.mycompany.com
    RackBaseURI /

    DocumentRoot /home/ubuntu/mycompany/public
    <Directory /home/ubuntu/mycompany/public >
     Options FollowSymLinks
     AllowOverride None
     Order allow,deny
     Allow from all
    </Directory>
</VirtualHost>

and

<VirtualHost _default_:443>
  ServerName shop.mycompany.com
  SSLEngine On

  ProxyPass / http://localhost/
  ProxyPassReverse / http://localhost/
  ProxyPreserveHost On

  SSLCertificateFile /etc/ssl/...
  SSLCertificateKeyFile /etc/ssl/...
  SSLCertificateChainFile /etc/ssl/...
</VirtualHost>

I know this is not ideal at all. There must be a better way. I do not want all requests to go through https due to the overhead.

Mike