I launch the testing/unstable Debian network CD installation, it's a 2.4.22-1 kernel. (bf24 option doesn't seem to exist with this CD)
On RedHat I launch a 2.4.20 kernel and it's works.
I try to load the Red Hat compiled module by copy it on a floppy, them reboot with Debian install CD and "cp ciss.o /lib/modules/2.4.22/kernel/drivers/block". But it doesn't work [Lot of "unresolved symbol" ].
I try with "insmod", "insmod -f" and "modprobe cciss".
So i'll try to create a custom Debian Boot floppies and come back to say if it works....