I added a 2nd SCSI disk to my e-smith box, no problem.
1. "format /dev/sdb" (2nd scsi disk), and create your partitions using the "fdisk" option
2. "mke2fs /dev/sdb1" to create your filesystem on the new partition
3. "mkdir /work" (that's where I mounted my 2nd drive's partition)
4. "mount /dev/sdb1 /work" to actually attach it.
Check your results with "df -k" and you should see your new partition and mount point, along with sizes total, used, etc.
5. Update "/etc/fstab" with your new partition information. (see the entries in there already for layout.
It worked for me, so it should work for you!
Good luck!
David Barber
DB Computers
Komoka, Ontario