Only use free membership levels when upgrading

Hi

I'm using the membership plugin.
I would like to use the free membership gateway for all my subscription plans. I will then handle the payments by invoice.

When I use free payment as gateway I don't get a subscribe button though. When I'm using paypal there is a button that lets me fill in the payment details.

Also, no matter if I use the paypal or free subscription I don't get any subscribe -buttons or price on the subscription page. See attached screenshot.

Thanks!