Moving below or right with the Enter key

[frerejacque <daniel frerejacque free fr>]

Gnumeric 1.2.8
To validate the input in a cell,
there is two ways:
        after entering data
        1) use key Tab (right) to access the cell at the right
        2) use (Enter/Return) the same key on a laptop then
        you move to the cell below the one you just validate.
Remark: After entering the current date (Ctl = ;)
        you can only validate with the key Enter/Return
Question:
        How to customise the Enter key
        to access either the right cell or the cell below
        at will.
(I notice that Shift+Enter goes up one cell in the column.

Thanks
Daniel Frerejacque