FreeBSD 8.0 not detecting hot swap drive insertion

[Rob]

I'm running a 10 hot-swap SATA disk ZFS pool and recently upgraded from 
7.2 to 8.  Since I upgraded, freebsd isn't spinning up or recognizing a 
new drive that is inserted.  In freebsd 7.[0,2], I could remove a drive 
and insert a new one and freebsd would recognize it, spin it up, and 
create the device nodes.  None of that is happening in 8.0, and the only 
way I've found to get it to recognize the disk is to reboot the system.

I tried using atacontrol to force freebsd to reinit an ata channel, but 
that didn't have any effect.  Did something change in 8.0 that prevents 
this auto-detection?  Is there a way to re-enable it?

Rob