My instructions from Intrepid turned out to be unnecessarily complex in Jaunty (probably was in Intrepid too). I just had to copy the firmware files from the original CD (still have it), moved them now to my home partition, and add the file reference to the /etc/sane.d/snapscan.conf file.
All the other instruction seem unnecessary! Yay!
Same applies to openSUSE 11.1
Make sure you have the scanner actually plugged in.