Need to pass target URL in API call

Hi! I have a suite of tests (job) that we are planning to run in different azure slots, so the entry URL will need to change on demand. I was expecting to do an API POST like this:

{
  "testParameters": [
    {
      "testId": "XAi-BhHuPk6TuOIHgU4IRg",
      "data": [
        {
          "baseURLforTransaction": "google.com"
        }
      ]
    }
  ]
}

unfortunately, the baseURLforTransaction parameter I used on the tests is not being overwritten with the values in the call.

Is there something I’m missing?