Need execution type as Manual while using Zephyr API to execute test

I need to update manual test execution through API. This is because all who execute tests are not having access to Zephyr. But the problem is when we update test using API it marks the test as Automated which creates wrong report. Is there a way to use API and mark the test as Manual?

In the documentation, I found "When you post a test-execution result using the API and include a username, it appears as a manual execution. This design allows you to mark an execution as manual, even if it was added via the API."

But when I tried using username in body or header, it still marks the test as Automated.