[blaiserulez]

As root I had to create a /dev/scanner folder and a link to the /dev/scsi/sc2d1l0 item (this represent my scanner on the scsi controller2):
ln -s /dev/scsi/sc2d1l0 /dev/scanner

Are you sure /dev/scanner is supposed to be a "folder" (or "directory" as it is called in Unix)?  I would think that it should be a direct link /dev/scanner -> /dev/scsi/sc2d1l0.  In other words, you should NOT create the "folder" (or remove the existing one);  just type the "ln" command as given above to create a direct link rather than a link in a folder.  (But again, that's my speculation.  I'm not 100% sure of the above.)

The link is created (I see it with italic letters on the desktop) it is a 17Bytes file (link) permissions: rwx/r-x/r-x

The 17 bytes looks right.  The permissions don't.  I think they should be rw-rw-rw-.  I don't see why you'd need execute permission (the 'x' bit), but you would need write permission ('w') to send SCSI commands to it.  Try that first, before the above suggestion.

The original item in /dev/scsi/ is 0Bytes long and had the permissions rw-/---/--- as the other scsi items.

That is perfectly normal.  The files under /dev aren't real files.  They're special to the operating system kernel.

Thank You, jpstewart! I removed the /dev/scanner directory and created the direct link. With the link the scanner is working perfectly.
Now I have a working large format scanner at home again... It's a huge monster