Configurable sender for response templates

[paddycarver]

When creating response templates, it looks like the sender for the template is stored in the database, and is in theory configurable. At the moment, however, that's not exposed in the UI, and updating it manually in the Datastore (and clearing the cache) hasn't worked. We're hoping we could configure a Google Group address as the sender of the email. According to the docs, we should be able to add any user in our domain, or any group we're a manager or owner of, as an authorized sender of mail. If we could configure isthislegit to use one of those senders, that would be awesome.