  We derive fully covariant expressions for all two-point scattering amplitudes
of two massless closed strings from a Dirichlet $p$-brane. This construction
relies on the observation that there is a simple relation between these D-brane
amplitudes in type II superstring theory and four-point scattering amplitudes
for type I open superstrings. From the two-point amplitudes, we derive the long
range background fields for the D-branes, and verify that as expected they
correspond to those of extremally charged $p$-brane solutions of the low energy
effective action.
