  We study chargino production at a muon collider with longitudinally polarized
beams and center of mass energies around the heavy neutral Higgs boson
resonances. We show that the interference of the CP even and CP odd Higgs
bosons can be analyzed using the energy distributions of the lepton or W boson
from the chargino two-body decays \tilde\chi^\pm_j\to\ell^\mp\tilde\nu_\ell or
\tilde\chi^\pm_j \to W^\pm \neutralino_1, respectively. The energy
distributions depend on the longitudinal polarization of the decaying chargino,
which are correlated to the muon beam polarizations. We define asymmetries in
these energy distributions which allow a determination of the H and A couplings
to the charginos and in particular of their relative phase. We analyze the
asymmetries, cross sections and branching ratios in CP conserving Minimal
Supersymmetric Standard Model scenarios. For nearly degenerate Higgs bosons we
find maximal asymmetries which can be measured with high statistical
significance.
