We consider the sinh-Poisson equation (P)_\lambda\quad -\Delta u=\la\sinh
u\ \hbox{in}\ \Omega,\ u=0\ \hbox{on}\ \partial\Omega, where Ω is a
smooth bounded domain in \rr^2 and λ is a small positive parameter.
If 0∈Ω and Ω is symmetric with respect to the origin, for any
integer k if \la is small enough, we construct a family of solutions to
(P)_\la which blows-up at the origin whose positive mass is 4πk(k−1) and
negative mass is 4πk(k+1).
It gives a complete answer to an open problem formulated by Jost-Wang-Ye-Zhou
in [Calc. Var. PDE (2008) 31: 263-276]