I found the answer.
VDP uses Apache HTTPD (Apache2).
There is directory /etc/apache2 with what you need.
certificate is in ssl.crt
private key is in ssl.key
configuration file is in vhost.d
server.crt (the certificate) must be a leaf only, not a chain.
The intermediate/root chain goes in ca.crt (in reverse order with intermediate certificates first, and the root last)
Ciphers and encryption suites can be changed using the .conf file in vhost.d
Restart the apache server after you replace the files and adjust the .conf file using
sudo service apache2 restart