Thanks again mate!
I was preparing for the process of copying the vfat-img to the internal flash-memory which, imho (but I'd like to see myself as a n00b), will render the Readynas into a nice brick, hence the hesitation.
Meanwhile, I've indeed copied the *vfat.img to internal flash memory, just tried the bootstrap-script for Atom D410, rebooted and got myself the ipkg-command:-)
Did a "ipkg update" and "ipkg upgrade", then installed the packages mentioned to silence the fans.
In that process, added bash-shell through "ipkg install bash" to follow the original posters solution as much as possible and rebooted the Readynas.
Unfortunately, fan still running at full speed, but checking the start from the fan control daemon, must be something wrong with it.
Thank you very much for your contribution.
P.s. I'm told that the lcd CAN be put to work. I picked up the following init-script from nexentastor.org:
$ cat /etc/init.d/lcd
#!/bin/bash
echo "E" > /dev/term/b
sleep 0.5
echo "L NexentaStor" > /dev/term/b