> Unfortunately, my system doesn't have sg_scan (perhaps I could install
> this).

There is another script you can use for rescanning devices on a SCSI interface
that works quite well. The output looks quite similar to that the sg_scan
script does. You can find it here:

http://www.garloff.de/kurt/linux/rescan-scsi-bus.sh

Not sure if it would help at but it's worked for me adding new devices
including having the dev nodes created even for devices that seemed to have
magically disappeared.

--
Lonny Selinger LPIC-1
-- 
"To mess up a Linux box, you need to work at it; to mess up your Windows box,
you just need to work ON it."