If one try to add single scattering to one of the standard physics lists by adding the __SS option nothing will happen as option 8 for electromagnetic processes is not implemented in the file G4PhysListFactory.cc Discussed in the geant4 forum here: http://hypernews.slac.stanford.edu/HyperNews/geant4/get/emprocess/1466.html
Hi Helga, thank you very much for spotting the bug. The fix is known and will be publicly available for the next public release of Geant4 in June. VI