In the present paper, we show, by means of numerical simulations, that electromagnetic field data obtained from the radiation of a return-stroke lightning discharge and measured over a short-duration time-window can be exploited to reconstruct the attenuation function of the lightning channel. To this end, we discretize the current-field equations derived in the first part of this work and then formulate an inversion algorithm whose output is the attenuation function to be computed. Next, as a numerical application, this algorithm is tested under different conditions, i.e., by considering a variety of time windows and underlying models for the attenuation function. As a result, the possibility of obtaining satisfactory reconstructions, even for short-duration time-windows, is highlighted.