Using Azure Application Gateway as Ingress

I have an application setup on AKS (Azure Kubernetes Service) and I’m currently using Azure Application gateway as ingress resource for my application running on AKS.

Now after setting up ISTIO for my cluster the graphs are coming up fine except one part. Since the Azure APP gateway is unknown to ISTIO it is showing the resource as “unknown”. I even tried launching a virtual service and pointed it to the ingress resource but that didn’t have any effect on the graph. How shall I establish to ISTIO that it is Azure app gateway and not “unknown” resource.