  We compute the boundary scattering amplitudes of the breathers of the
supersymmetric sine-Gordon model using the fusion of the soliton-antisoliton
pair scattering with the boundary with a known result of the soliton boundary
scattering amplitudes. We also solve the boundary Yang-Baxter equation of the
eight-vertex free fermion models to find the boundary reflection matrices. The
former result is confirmed by the latter since the bulk $S$-matrices of the
breathers can be identified with the trigonometric limit of the Boltzmann
weights of the free fermion models. Our dual approach can answer a few quesions
on the relationships between the free parameters in the boundary potential and
those in the scattering amplitudes.
