[SLE] Please help with ieee1394 drive.

Hi all, I own a 250 GB ieee1394 drive which works well under SuSE 9.2 and 9.3 Pro, but only if I hotplug it, It is not detected if connected at boot. I saw in file /sys/bus/ieee1394/rescan : "You can force a rescan of the bus for drivers by writing a 1 to this file" But even as root, I don't seem to have acces permission to this file and this folder, and the command : echo 1 > /sys/bus/ieee1394/rescan does nothing !! What do I miss, and how can I rescan the ieee1394 bus ? Thanks in advance for your help. Michel