Since I use the numpad keys to write letters on the default and Shift layer, I plan to write numbers with the extend layer of the numpad keys.
My attempts to give the numpad keys different tasks on the Extend layer by editing _eD_Extend.ini did not change the output from the default, however.
I first tried the formatting of the rest of the file:
Co_P_4 = t
Co_P_5 = e
Co_P_6 = s
Co_P_7 = t
and then afterwards tried if scan code would work:
sc04b = t
sc04c = e
sc04d = s