  Within the context of type I strings, we show the equivalence between BPS D9
branes with internal magnetic fluxes H_i in the three torii and non-BPS D3
branes with inverted internal magnetic fluxes 1/H_i. We then construct new
supersymmetric examples of Z_2 x Z_2 orientifolds with discrete torsion which
in the past had only non-supersymmetric solutions and emphasize the role of new
twisted tadpole cancellation conditions, arising in the presence of magnetic
fields, in order to get a consistent spectrum. In a second and independent part
of the paper, we construct a new nine-dimensional type IIB orientifold with
Scherk-Schwarz deformation which has the peculiarity of introducing a new type
of non-BPS O9 planes and which contains as top branes a Scherk-Schwarz
deformation of non-BPS D9 branes.The model contains charged D7 and D3 branes
with a soft supersymmetry breaking spectrum.
