There's an Inferno for the discussion of all aspects of Inferno and Limbo
(which would include acme-sac because it's built on that).

To subscribe to that list, send a message to inferno-list-request@vitanuova.com,
including the word "subscribe" in the subject or body of the message.

There is, however, acme-sac specific discussion in an associated Google group.
Go to http://code.google.com/p/acme-sac/  and look at the Groups link in particular.
You might want to try that group first, since it's most specific.