You don't need a CA certificate. The self-signed certificate on your system expired after 5 years and the new one you generated will be good for the next 5 years. It is only used to secure the connection between your browser and the SAN.
We recently had an issue where the certificates on our VNX SANs expired and we were not able to access the SANs. I regenerated the certs by logging into the Setup page of each SAN and regenerating the certs from there and it all works good now.  However my manager insists that I need to generate a cert request, convert it to a domain cert using our CA server and upload it into the SAN. My question is thus, if the self-generated cert is OK then why would I need a domain cert?
Are CA certificates required with VNX SANs?