  We consider a supersymmetric version of the standard model extended by an
additional U(1)_{B-L}. This model can be embedded in an mSUGRA-inspired model
where the mass parameters of the scalars and gauginos unify at the scale of
grand unification. In this class of models the renormalization group equation
evolution of gauge couplings as well as of the soft SUSY-breaking parameters
require the proper treatment of gauge kinetic mixing. We first show that this
has a profound impact on the phenomenolgy of the Z' and as a consequence the
current LHC bounds on its mass are reduced significantly from about 1920 GeV to
1725 GeV. They are even further reduced if the Z' can decay into supersymmetric
particles. Secondly, we show that in this way sleptons can be produced at the
LHC in the 14 TeV phase with masses of several hundred GeV. In the case of
squark and gluino masses in the multi-TeV range, this might become an important
discovery channel for sleptons up to 650 GeV (800 GeV) for an integrated
luminosity of 100 fb^{-1} (300 fb^{-1}).
