I was able to get CAC authentication working through the FTD.  The high level steps are below.  TAC was a huge help on this ticket.  You must have the proper cert chain which issued the user certificates installed in Devices-Certificates.  For exampl...

Eric, thank you for your help so far. I am stuck too.  Please post updates to your TAC case here.  I'll get our account rep to try to prioritize this. ss