How to verify a certificate by configuring route of cloud foundary

I want to do mutual authentication with clients as said in Cloud Foundary Docs: https://docs.cloudfoundry.org/adminguide/securing-traffic.html

But I don't know how to configure it in BTP Cloud Foundary:

When I click bind route service, the combox box is empty:

Kindly ask that how can I configure it to enable mtls.

My Scenario: server x call my cf app in BTP. Server x only support mtls(client certificate) way. So we will configure a certificate and key both in server x and cf apps in BTP. Then I suppose CF router will help do mtls auth.

Thank you.