  The study of radiative phi decays into scalar mesons, with subsequent decay
into pi pi gamma, constitutes an important topic at the electron-positron
collider DAPHNE. The interference of the respective amplitude with the one for
pi+ pi- gamma production, where the photon originates from initial state
radiation, will allow for unambiguous tests of models for the phi -> gamma
f0(-> pi pi) amplitude.
  The forward-backward asymmetry of charged pions, which is a clear signal of
such an interference, amounts up to 30 % and is at the same time quite
sensitive to the details of the various amplitudes.
  The results for several characteristic cases are presented and their
implementation into the Monte Carlo generator PHOKHARA is described.
