Question: For some reason my Naviate REX cuts off my beam-reinforcement when the beam is lying f.ex. 30cm on a wall opening. 

Answer: Naviate Rebar Extension automatically divides stirrup distribution in field (between support) and stirrup distribution above support. To add stirrups above support it is needed to activate this left check-box ("Left support ") and define distribution of stirrups in "SL" (spacing).