  We study the pair-production of charginos in the CP-violating Minimal
Supersymmetric Standard Model at center-of-mass energies around the heavy
neutral Higgs boson resonances. If these resonances are nearly degenerate, as
it can happen in the Higgs decoupling limit, radiatively induced
scalar-pseudoscalar transitions can be strongly enhanced. The resulting mixing
in the Higgs sector leads to large CP-violating effects, and a change of their
mass spectrum. For longitudinally polarized muon beams, we analyze CP
asymmetries which are sensitive to the interference of the two heavy neutral
Higgs bosons. We present a detailed numerical analysis of the cross sections,
chargino branching ratios, and the CP observables. We obtain sizable
CP-asymmetries, which would be accessible in future measurements at a muon
collider. Especially for intermediate values of the parameter \tan\beta, where
the largest branching ratios of Higgs bosons into charginos are expected, this
process allows to analyze the Higgs sector properties and its interaction to
supersymmetric fermions.
