Hello, I think that MassMessage should automatically use signature, date and time for DiscussionTools. When is there no signature, date and time, it is not possible to reply using Reply Tool (the part of DiscussionTools). It is a pity when I cannot reply to a message posted by MassMasage. This should be a big problem when Reply Tool will be available at all Wikimedia project.
(Furthermore, I personally think that it makes a lot of sense not to be able to reply to MassMessages in hundreds of places, where the senders of a MassMessage will never see all those replies anyway. I personally believe that good MassMessages explain in which one single place readers could reply instead.)