Class Team activation (using MicrosoftTeams preview)

Hi all,
I'm using the MicrosoftTeams (preview version) to create Class Teams. Creating Teams seems to work and so does adding channels to Teams. However, adding users (as member) to the team doesn't fully succeed since the Team created is by default not "activated" (students are set to wait for admission to the Team). Since it's not activated no users can be added to the channels either. Unfortunately I was asked to create Teams for each course in our school, create a fixed number of channels in each and populate the members of those Teams AND channels with students. This works if I manually (i.e. through the web GUI) press the "Activate" button for the Team. Can anyone point me to some relevant info on how to automate this "activation" of Class Teams (preferably also in Powershell)?
Regards, Kris.