Optional Rule Guide Manual defensive fire

[LarkinVB]

My Campaign Waterloo does not have any Automated Defenive Fire option. Is this only in the ACW games available?

So the best way to play ACW PBEM games with only one file per turn is with MDF off and ADF on? I'm a bit confused now.

The Auto DF fire dialog for setting ranges is not with the options dialog. So can this be set on a turn by turn basis and how does this work in email games? When it is my turn I can set the values but in this turn my enemy is firing automated. So will I set the values for my enemy?