  We discuss various D-brane configurations in 4-dimensional orbifold
compactifications of type II superstring theory which are point-like 0-branes
from the 4-dimensional space-time point of view. We analyze their interactions
and compute the amplitude for the emission of a massless NSNS boson from them,
in the case where the branes have a non vanishing relative velocity. In the
large distance limit, we compare our computation to the expected field theory
results, finding complete agreement.
