We elaborate on a new N=2, d=3 supermultiplet (double-vector multiplet) with
a non-trivial off-shell realization of the central charge. Its bosonic sector
comprises two abelian gauge vector fields forming an SO(2) vector. We present a
superfield formulation of this multiplet in the central-charge extended N=2,
d=3 superspace and then employ it, in the framework of the nonlinear
realizations approach, as the Goldstone one for the partial breaking N=4 -> N=2
in three dimensions. The covariant equations of motion for the self-interacting
Goldstone superfield arise as a natural generalization of the free ones and are
interpreted as the worldvolume supersymmetric form of the equations of motion
of a N=4 D2-brane. For the vector fields we find a coupled nonlinear system of
Born-Infeld type and demonstrate its dual equivalence to the d=5 membrane. The
double-vector multiplet can be fused with some extra N=2, d=3 multiplet to form
an off-shell N=4, d=3 supermultiplet.Comment: 11 pages, no figures, typos corrected, version to be published in PL