Sandro,
What exactly is the task that needs to be documented? Is it enabling channels for the RHVM appliance and updating the appliance, in order to update the RHVM VM, and then updating the RHVM VM?
Are we only talking about updating to the latest z stream?
We want to document how to write an Ansible playbook that runs on the engine VM before and after running engine-setup. The task is documented for upstream at the github link in comment 0.