I think the pattern would be: both multiselectors side by side, and arrows to left and right indicating moving options from left selector to the right and viceversa (instead of add and remove buttons).
Also its better to physically remove options from selector "From", instead of greying them, once they are "moved" tho selector "To".
-- Enrique Meléndez Estrada (2367) Servicios Informáticos Organización y Servicios Internos Instituto Tecnológico de Aragón
