  It has been argued recently that mirror symmetry exchanges two pure spinors
characterizing a generic manifold with SU(3)-structure. We show how pure
spinors are modified in the presence of topological D-branes, so that they are
still exchanged by mirror symmetry. This exchange emerges from the fact that
the modified pure spinors come out as moment maps for the symmetries of A and
B-models. The modification by the gauge field is argued to ensure the inclusion
into the mirror exchange of the A-model non-Lagrangian branes endowed with a
non-flat connection. Treating the connection as a distribution on an ambient
six-manifold, assumed to be T^3-fibered, the proposed mirror formula is
established by fiberwise T-duality.
