  In this paper we reopen the discussion of gauging the two-dimensional
off-shell (2,2) supersymmetric sigma models written in terms of semichiral
superfields. The associated target space geometry of this particular sigma
model is generalized Kahler (or bi-hermitean with two non-commuting complex
structures). The gauging of the isometries of the sigma model is now done by
coupling the semichiral superfields to the new (2,2) semichiral vector
multiplet. We show that the two moment maps together with a third function form
the complete set of three Killing potentials which are associated with this
gauging. We show that the Killing potentials lead to the generalized moment
maps defined in the context of twisted generalized Kahler geometry. Next we
address the question of the T-duality map, while keeping the (2,2)
supersymmetry manifest. Using the new vector superfield in constructing the
duality functional, under T-duality we swap a pair of left and right semichiral
superfields by a pair of chiral and twisted chiral multiplets. We end with a
discussion on quotient construction.
