  We study the diffusive and localization properties of wavepackets in
disordered wires in a magnetic field. In contrast to a recent supersymmetry
approach our numerical results show that the decay rate of the steady state
changes {\em smoothly} at the crossover from preserved to broken time-reversal
symmetry. Scaling and fluctuation properties are also analyzed and a formula,
which was derived analytically only in the pure symmetry cases is shown to
describe also the steady state wavefunction at the crossover regime. Finally,
we present a scaling for the variance of the packet which shows again a smooth
transition due to the magnetic field.
