I was hopping to avoid using Forms. But after I tought about it, it is not possible to initialize a default value of a field using another field in the same table. Because it will assume the field to be initialized must be created after the field that will be used to for initialization. The default value is set when a field is created. If both field are created and they are both blank, the default value will be always blank.
Thank you Remou for trying.
SolEsk