Elastic Cloud: How to enable x-pack Machine Learning?

Elastic Version: 6.1.1
when I set xpack.ml.enabled: true it shown illegal user settings.
I want to know could Elastic Cloud enable ML
will Elastic Cloud support ML in the future and when?

Please see https://www.elastic.co/cloud/as-a-service/support for Elastic Cloud support.

We will be enabling ML in the Cloud in the near future, we don't have a timeframe at this stage though sorry.