Does IngressRouteTCP support different services than externalName

Traefik Traefik v2
,
1

Hello,
I´m trying to use the kubernetes crd provider to configure TCP services, but it seems that I cannot use any other Kubernetes service kind than externalName to get this running.
The documentation is not very specific about that:
https://docs.traefik.io/master/routing/providers/kubernetes-crd/#kind-ingressroutetcp
I want to use the ClusterIP service for cluster-internal communication and don´t want to create another Service just for tcp traffic. Do you kindly have any advice for me?
Doesn´t work:

apiVersion: traefik.containo.us/v1alpha1
kind: IngressRouteTCP
metadata:
  name: central-whoami-frontend-sftp
  namespace: whoami-dev
spec:
  entryPoints:
    - whoamisftp
  routes:
    - match: HostSNI(`*`)
      services:
        - name: whoami-frontend-20200512113419
          port: 7722
          weight: 10
          terminationDelay: 400
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app.kubernetes.io/instance: whoami-frontend-20200512113419
    app.kubernetes.io/name: whoami-frontend
  name: whoami-frontend-20200512113419
  namespace: whoami-dev
spec:
  type: ClusterIP
  ports:
    - name: sftp
      port: 7722
      protocol: TCP
      targetPort: 7722
    - name: rest
      port: 7080
      protocol: TCP
      targetPort: 7080
  selector:
    app.kubernetes.io/instance: whoami-frontend-20200512113419
    app.kubernetes.io/name: whoami-frontend

Does work (IngressRouteTCP is pointing to externalName service):

apiVersion: traefik.containo.us/v1alpha1
kind: IngressRouteTCP
metadata:
  name: central-whoami-frontend-sftp
  namespace: whoami-dev
spec:
  entryPoints:
    - whoamisftp
  routes:
    - match: HostSNI(`*`)
      services:
        - name: whoami-frontend-20200512113419-traefik
          port: 7722
          weight: 10
          terminationDelay: 400
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app.kubernetes.io/instance: whoami-frontend-20200512113419
    app.kubernetes.io/name: whoami-frontend
  name: whoami-frontend-20200512113419
  namespace: whoami-dev
spec:
  type: ClusterIP
  ports:
    - name: sftp
      port: 7722
      protocol: TCP
      targetPort: 7722
    - name: rest
      port: 7080
      protocol: TCP
      targetPort: 7080
  selector:
    app.kubernetes.io/instance: whoami-frontend-20200512113419
    app.kubernetes.io/name: whoami-frontend
---
apiVersion: v1
kind: Service
metadata:
  name: whoami-frontend-20200512113419-traefik
  namespace: whoami-dev
spec:
  externalName: whoami-frontend-20200512113419.whoami-dev
  type: ExternalName
  ports:
    - port: 7722