Hi again, and thank you all! Problem solved ─ Julien, you had it right: although I find it weird to have `(xorg-configuration (xorg-configuration ... ))`, this is what works! But I guess it is just like `(keyboard-layout (keyboard-layout ... ))`...
Best regards, Cássio -- ----- Faculdade de Letras - UFG *“* *Ou a gente se Raôni, ou a gente se Sting**”*