  {\it Perturbiner}, that is, the solution of field equations which is a
generating function for tree form-factors in N=3 $(N=4)$ supersymmetric
Yang-Mills theory, is studied in the framework of twistor formulation of the
N=3 superfield equations. In the case, when all one-particle asymptotic states
belong to the same type of N=3 supermultiplets (without any restriction on
kinematics), the solution is described very explicitly. It happens to be a
natural supersymmetrization of the self-dual perturbiner in non-supersymmetric
Yang-Mills theory, designed to describe the Parke-Taylor amplitudes. In the
general case, we reduce the problem to a neatly formulated algebraic geometry
problem (see Eqs(\ref{5.15i}),(\ref{5.15ii}),(\ref{5.15iii})) and propose an
iterative algorithm for solving it, however we have not been able to find a
closed-form solution. Solution of this problem would, of course, produce a
description of all tree form-factors in non-supersymmetric Yang-Mills theory as
well. In this context, the N=3 superfield formalism may be considered as a
convenient way to describe a solution of the non-supersymmetric Yang-Mills
theory, very much in the spirit of works by E.Witten \cite{Witten} and by
J.Isenberg, P.B.Yasskin and P.S.Green \cite{2}.
