Kiali - No traffic showing from "Passthrough cluster"

Question

I'm running an AKS (Kubernates on Azure) cluster, with their own Istio plugin (Puts istio into aks-istio).

As a result, I've had to jump through some config hoops to redirect everything to the right namespace for Istio - everything works.

Apart from Kiali - I'm not seeing any outbound traffic beyond Pass Through Cluster.

I do have REGISTRY_ONLY set, and it works, as soon as I remove my Service Entries traffic stops - but I'd like to be able to see traffic out.

I presume it's because I don't have Prometheus setup correctly - as I can't find any references to PassThrough Cluster in my data - but also, no docs to help set it up.

I have two Service Monitiors setup - which bring through the bulk of my traffic - just missing the cluster.

    {
    "apiVersion": "monitoring.coreos.com/v1",
    "kind": "ServiceMonitor",
    "metadata": {
        "labels": {
            "monitoring": "istio-dataplane",
            "release": "prometheus"
        },
        "name": "prometheus-oper-istio-dataplane",
        "namespace": "monitoring",
"spec": {
    "endpoints": [
        {
            "interval": "15s",
            "path": "/stats/prometheus",
            "relabelings": [
                {
                    "action": "keep",
                    "regex": "istio-proxy",
                    "sourceLabels": [
                        "__meta_kubernetes_pod_container_name"
                    ]
                },
                {
                    "action": "keep",
                    "sourceLabels": [
                        "__meta_kubernetes_pod_annotationpresent_prometheus_io_scrape"
                    ]
                },
                {
                    "action": "replace",
                    "regex": "([^:]+)(?::\\d+)?;(\\d+)",
                    "replacement": "$1:$2",
                    "sourceLabels": [
                        "__address__",
                        "__meta_kubernetes_pod_annotation_prometheus_io_port"
                    ],
                    "targetLabel": "__address__"
                },
                {
                    "action": "keep",
                    "regex": ".*-envoy-prom",
                    "sourceLabels": [
                        "__meta_kubernetes_pod_container_port_name"
                    ]
                },
                {
                    "action": "labelmap",
                    "regex": "__meta_kubernetes_pod_label_(.+)"
                },
                {
                    "action": "replace",
                    "sourceLabels": [
                        "__meta_kubernetes_namespace"
                    ],
                    "targetLabel": "namespace"
                },
                {
                    "action": "replace",
                    "sourceLabels": [
                        "__meta_kubernetes_pod_name"
                    ],
                    "targetLabel": "pod_name"
                }
            ],
            "targetPort": "http-envoy-prom"
        }
    ],
    "jobLabel": "envoy-stats",
    "namespaceSelector": {
        "any": true
    },
    "selector": {
        "matchExpressions": [
            {
                "key": "istio-prometheus-ignore",
                "operator": "DoesNotExist"
            }
        ]
    }
}

}

{
    "apiVersion": "monitoring.coreos.com/v1",
    "kind": "ServiceMonitor",
    "metadata": {
        "labels": {
            "release": "prometheus"
        },

        "name": "prometheus-oper-istio-controlplane",
        "namespace": "monitoring",
        "resourceVersion": "1152559",
        "uid": "6c4a1080-e2ff-456c-ae86-23caaf73fe73"
    },
    "spec": {
        "endpoints": [
            {
                "interval": "15s",
                "port": "http-monitoring"
            },
            {
                "interval": "15s",
                "port": "http-policy-monitoring"
            }
        ],
        "jobLabel": "istio",
        "namespaceSelector": {
            "any": true
        },
        "selector": {
            "matchExpressions": [
                {
                    "key": "istio",
                    "operator": "In",
                    "values": [
                        "mixer",
                        "pilot",
                        "galley",
                        "citadel",
                        "sidecar-injector"
                    ]
                }
            ]
        }
    }
}