  We revisit the Hanany-Witten brane construction of 3d gauge theories with N=2
supersymmetry. Instantons are known to generate a superpotential on the Coulomb
branch of the theory. We show that this superpotential can be viewed as arising
from the classical scattering of domain wall solitons. The domain walls live on
the worldvolume of the fivebranes and their existence relies on the recent
observation that the charged hypermultiplet at the intersection of
perpendicular D-branes has non-canonical kinetic terms. We further show how Dp
branes may be absorbed at the intersection of perpendicular D(p+4)-branes where
they appear as BPS sigma-model lumps.
