I am setting a reverse proxy using kubernetes nginx-ingress, but I don't know how to add nginx parameters to the configuration, specifically: proxy_ssl_server_name. How do I set ingress parameters in yaml configurations?

I already tried using the server-snippet annotation, but it seems like it's not adding the parameter to the nginx.conf file in the cluster pods.

Here is the current code for the reverse proxy:

kind: Service
apiVersion: v1
metadata:
  name: formstack
  namespace: serves
spec:
  type: ExternalName
  externalName: fluidsignal.formstack.com
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: formstack
  namespace: serves
  annotations:
    kubernetes.io/ingress.class: nginx
    nginx.ingress.kubernetes.io/upstream-vhost: "fluidsignal.formstack.com"
    nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
spec:
  tls:
  - hosts:
    - fluidattacks.com
    secretName: fluidattacks-cert
  rules:
  - host: fluidattacks.com
    http:
      paths:
      - backend:
          serviceName: formstack
          servicePort: 443
        path: /forms(.*)

After setting up the proxy, I get a 502 Bad Gateway error from Nginx. After looking at the pods logs, I see I'm getting the following openssl error: SSL: error:14094410:SSL routines:ssl3_read_bytes:sslv3 alert handshake failure:SSL alert number 40, which is why I want to add the parameter I mentioned before.