  Lorentzian signature D-branes of all dimensions for the Nappi-Witten string
are constructed. This is done by rewriting the gluing condition $J_+=FJ_-$ for
the model chiral currents on the brane as a well posed first order differential
problem and by solving it for Lie algebra isometries $F$ other than Lie algebra
automorphisms. By construction, these D-branes are not twined conjugacy
classes. Metrically degenerate D-branes are also obtained.
