Nonlinear system regulation is an active research area and is important for disturbance rejection and reference signal tracking, Existing results using differential geometry or Lyapunov theory are restricted to bounded exogenous signals. This paper uses a differential vector space approach to develop solutions for nonlinear system regulation with both bounded and unbounded exogenous signals. The solutions are given in terms of observable dual state spaces in the differential vector space of the system and are well suited to symbolic and numerical computation.