  A superspace formulation using superconnections and supercurvatures is
specifically constructed for N=4 extended super Yang-Mills theory with a
central charge in four dimensions, first proposed by Sohnius, Stelle and West
long ago. We find that the constraints, almost uniquely derived from the
possible spin structure of the multiplet, can be algebraically solved which
results in an off-shell supersymmetric formulation of the theory on the
superspace.
