Adaptec 5805 and SAS disks not attaching

[Kurt Lidl]

I recently got a used server, that has an Adaptec 5805 raid controller
in it.

I bought a couple of enterprise SAS disks.

After sorting out the mounting hardware for the machine, I booted
a stock FreeBSD 10.2 memory stick on the machine.

However, the disks don't attach as daX devices.  I have tried
configuring the drives as "JBOD", and get the same results.  I have
tried configuring the drives with neither a RAID or JBOD on them,
so the controller can just pass them through to the OS.
(It's my intention to run ZFS on the drives.)

root@:~lidl # camcontrol devlist
<WD WD6001BKHG-02D22 SR07>         at scbus0 target 6 lun 0 (pass0)
<WD WD6001BKHG-02D22 SR07>         at scbus0 target 7 lun 0 (pass1)
<AHCI SGPIO Enclosure 1.00 0001>   at scbus9 target 0 lun 0 (pass2,ses0)
<USB DISK PMAP>                    at scbus10 target 0 lun 0 (da0,pass3)

Any ideas or obvious gotchas?  The controller attaches like this:

aac0: <Adaptec RAID 5805> mem 0xfba00000-0xfbbfffff irq 26 at device 0.0 
on pci7
aac0: Enabling 64-bit address support
aac0: Enable Raw I/O
aac0: Enable 64-bit array
aac0: New comm. interface enabled
aac0: Adaptec 5805, aac driver 2.1.9-1
aacp0 on aac0
aacp1 on aac0
aacp2 on aac0

Thanks for any insight.

-Kurt