You're right. The driver indeed did not match this device. Actually, BillyBobber has been trying to boot debian from his SCSI disk with the chipset AIC-7902 and has posted his messages on the General Support Forum here.

Here is a link I got from there for the correct aic79xx driver for AIC-7901/02

http://people.freebsd.org/~gibbs/linux/SRC/

Now I am planning to compile the kernel-source 2.4.27 with the above aic79xx module overwritten on it (via knoppix) and install a kernel on my SCSI disk. Do you foresee any potential problems with this approach ? Or is there a simpler way in knoppix to install a debian kernel image with the above aic79xx driver built in ?