Nuclear elastic scattering (NES) has recently been recognized as an important slowing down mechanism for fast ions injected into a background plasma. The present paper proposes an improved method to include this effect into slowing down calculations. This method consists of calculating multigroup cross-section data including the transfer matrices up to a desired degree of Legendre expansion and in supplying the data to a Boltzmann-Fokker-Planck (BFP) equation solved by a discrete ordinales scheme. The physical model of the BFP equation and the accuracy of the numerical method guarantee a good representation of NES.