Hi Abdess,
Like variables in normal programming, it is not necessary to be a input variable, it may calculate the value form others variables, reading directly from database etc.
Please check the property of the mentioned variables, I guess they are with setting:
Processing by: Customer Exit (Which mean some logic apply...)
Variable is Ready for input: Not clicked (Which mean it is not a input variable)
I will suggest you try to find some document about query variable and read on.
Regards
Bill
