CAM/SATA: attach/detach problems with harddrive

Hello.

Several maintenance of a ZFS pools has to be done and my intention was 
to swap the 2TB hd disk (WDC WD20EARS-00MVWB0) with a 3TB hd disk 
(WD30EZRX).

zfs umount works well,
zpool export POOL also worked well,

but I didn't find any "detach command" within camcontrol (I use the new 
AHACI/CAM layout in the kernel on FreeBSD 9.0-CURRENT/amd64 r223597, so 
my harddrives all show up as ada0 to ada4.
Since the box has a IcyDock 5-Slot backplane attached to the ICH0R 
chipset and camcontrol doesn't reveal any detach command like atacontrol 
did, I trusted in hotplugging capabilities and simply pulled the disk. 
All right, the box reported a lost device but did not crash. The I 
inserted the new drive. Entered

camcontrol rescan all

and

camcontrol devlist showed up the new device. But I can't do anything 
with the drive. Even with the former device inserted again, rescaned 
etc., a zpool import command get stuck as well as any diskinfo -ctv ada4 
issued to the device. The drive shows up in camcontrol devlist, but 
seems inoperable. What I'm doing wrong?

Oliver