  We study the semileptonic decays B -> Xs e+ e-, B -> Xs mu+ mu- in generic
supersymmetric extensions of the Standard Model. SUSY effects are parameterized
using the mass insertion approximation formalism and differences with MSSM
results are pointed out. Constraints on SUSY contributions coming from other
processes (e.g. b -> s gamma) are taken into account. Chargino and gluino
contributions to photon and Z-mediated decays are computed and non-perturbative
corrections are considered. We find that the integrated branching ratios and
the asymmetries can be strongly modified. Moreover, the behavior of the
differential Forward-Backward asymmetry remarkably changes with respect to the
Standard Model expectation.
