To change a virtual host in apache to ssl: 

#Redirect all normal traffic to the https site.
<VirtualHost *:80>
  RewriteEngine on
  RewriteRule ^/(.*) https://%{HTTP_HOST}/$1 [L,R]
</VirtualHost>
 
# This virtual host was *:80 first
<VirtualHost *:443>
   DocumentRoot /bla
   # If I don't specify this, nagios's check_ssl_cert doesn't work.
   ServerName www.joho.com
 
   # These lines were added to make it SSL
   SSLEngine on
   SSLCertificateFile    /etc/ssl/certs/ssl-cert-snakeoil.pem
   SSLCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key
   # if you have an official certificate, also add some of these:
   SSLCertificateChainFile /etc/ssl/certs/bla
 
   <Directory /bla>
      Order allow,deny
      Allow from all
      AllowOverride None
      Options -MultiViews FollowSymlinks Indexes
   </Directory>
 
</VirtualHost>