Virtual Bugzilla 3.2.x comes with pre-installed HTTPS support. Right after installation, you will be able to access Bugzilla through HTTPS.
The SSL certificates that are used by default are self-generated, and you will likely get a warning from the browser about authenticity of HTTPS connection. You can ignore this warning, or you can purchase SSL certificates for Apache and install them into /etc/apache2/ssl. (Make sure to assign a DNS name to your Bugzilla before purchasing SSL certificate — you will need to use Bugzilla's host name as a common name for the certificate.)
To further configure Bugzilla to use HTTPS, visit Parameters page and set sslbase and ssl parameters.