Thanks Yutaka, that works.
If one don’t know where to find that commands, he may want to follow this steps:
Start “Tools > All Commands > Tools > Quick Launch”
Search for “next cell”
Right click “Next Cell” > choose “Properties”
You will see Configuration dialog: Tab:Keyboard / Category:Edit / Command:Next Cell
Here you can assign the wanted keyboard key-combination.
Please note that that may be the configuration for ONE file type only (as e.g. *.txt or *.csv, or what ever you had currently open).
If you want to add a shortcut to another file-type, or to common configuration,
then close the dialog and open the wanted one from “Tools > Properties for ??? Configuration”