We consider generalised Scherk Schwarz reductions of supergravity and
superstring theories with twists by electromagnetic dualities that are
symmetries of the equations of motion but not of the action, such as the
S-duality of D=4, N=4 super-Yang-Mills coupled to supergravity. The reduction
cannot be done on the action itself, but must be done either on the field
equations or on a duality invariant form of the action, such as one in the
doubled formalism in which potentials are introduced for both electric and
magnetic fields. The resulting theory in odd-dimensions has massive form fields
satisfying a self-duality condition dA∼m∗A. We construct such theories
in D=3,5,7.Comment: Latex, 26 pages. References adde