Can extended duality uniquely explain the dilepton data in HICs at SPS?

Extended duality is used to explain the dilepton data of heavy-ion experiments at CERN-SPS. Taking into account the background contributions (hadronic cocktail, Drell-Yan, semileptonic decays of open charm) the spectral shapes of the CERES, NA38/50 and HELIOS-3 data in experiments with lead and sulfur beams can be well described, however, the normalizations of the sulfur beam data are problematic.