  Manifest N=2 supersymmetric hypermultiplet mass terms can be introduced in
the projective N=2 superspace formalism. In the case of complex
hypermultiplets, where the gauge covariantized spinor derivatives have an
explicit representation in terms of gauge prepotentials, it is possible to
interpret such masses as vacuum expectation values of an Abelian vector
multiplet. The duality transformation that relates the N=2 off-shell projective
description of the hypermultiplet to the on-shell description involving two N=1
chiral superfields allows us to obtain the massive propagators of the N=1
complex linear fields in the projective hypermultiplet. The N=1 massive
propagators of the component superfields in the projective hypermultiplet
suggest a possible ansatz for the N=2 massive propagator, which agrees with an
explicit calculation in N=2 superspace.
