  We present the complete set of Feynman rules producing the rational terms of
kind R_2 needed to perform any 1-loop calculation in the Electroweak Standard
Model. Our results are given both in the 't Hooft-Veltman and in the Four
Dimensional Helicity regularization schemes. We also verified, by using both
the 't Hooft-Feynman gauge and the Background Field Method, a huge set of Ward
identities -up to 4-points- for the complete rational part of the Electroweak
amplitudes. This provides a stringent check of our results and, as a
by-product, an explicit test of the gauge invariance of the Four Dimensional
Helicity regularization scheme in the complete Standard Model at 1-loop. The
formulae presented in this paper provide the last missing piece for completely
automatizing, in the framework of the OPP method, the 1-loop calculations in
the SU(3) X SU(2) X U(1) Standard Model.
