OS X Server & Time Machine for Active Directory Users In my setup, we have an OS X server, where the machine is bound to our Active Directory domain.  I am able to log onto the machine using AD users/credentials locally, with no problems.  However, when I configure and enable the 'Time Machine' service, I cannot seem to authenticate to the machine from my Mac.  I was wondering if there was something extra needed for the server to query AD, without having to configure local users.  Thanks!
Ok - I feel foolish.  I found the answer within minutes of posting the question.  Here is the answer:

https://discussions.apple.com/message/24844922#24844922

I had to enable 'File Sharing' on OS X Server as well, add an explicit folder (or drive) where the backups would go and add explicit permissions to that folder. You can allow 'everyone' to access it, but in my case, I have an AD Security group that contains all Mac users in the org.