[users@httpd] mod_md, VirtualHost, and mod proxy/reverse proxy

[Paul Leo]

Have an Apache Reverse Proxy  with VirtualHost snippets as follows:

<VirtualHost *:443>
  ServerName foo.somedomain.org
  ProxyPreserveHost On
    ProxyPass /  http://10.0.0.0:443/foo-app/
    ProxyPassReverse / http://10.0.0.0:443/foo-app/
</VirtualHost>    

</VirtualHost>
<VirtualHost *:443>
  ServerName staging.foo.somedomain.org
    ProxyPreserveHost On
    ProxyPass /  http://10.0.0.1:443/stagefoo-app/
    ProxyPassReverse / http://10.0.0.1:443/stagefoo-app/
</VirtualHost>

Am working through the configuration for MOD_MD.
Do I add the Proxy configuration to the MDDomain element?
If yes, where would the files used for the challenge reside, on the proxy 
server, or on the 10.0.0.1 server?

Thanks