Aside from IPv4, I'm working on getting IPv6 working on the Mikrotik's PPPoE client as well.
I've tried searching for a solution, but that's mostly about DHCPv6 client.
I work at an ISP and am in control of the BRAS and the AAA/RADIUS (FreeRADIUS) server.
Maybe it's more a RADIUS than a Mikrotik question, but perhaps I'm missing something here.

The PPPoE client is quite standard, with a username, password and outgoing interface.
In FreeRADIUS I use Framed-IPv6-Address (/128), have also tried Framed-IPv6-Prefix (/48), but I'm totally unsure what to use (also: are there other attributes?
Is there anything I need to configure on the Mikrotik, apart from a /64 advertisement on the LAN, to get IPv6 connectivity to the Internet?

Update: I got something working with NDRA from the BRAS / PPPoE server, but the requirements move more towards DHCPv6 IA_NA and DHCPv6 Prefix Delegation from the server.
Is there any basic configuration needed in order for this to work?