  We study the upper limits on the mass of the lightest and second lightest CP
even Higgs bosons in the (M+1)SSM, the MSSM extended by a gauge singlet. The
dominant two loop contributions to the effective potential are included, which
reduce the Higgs masses by 10 GeV. Since the coupling R of the lightest Higgs
scalar to gauge bosons can be small, we study in detail the relations between
the masses and couplings of both lightest scalars. We present upper bounds on
the mass of a 'strongly' coupled Higgs (R > 1/2) as a function of lower
experimental limits on the mass of a 'weakly' coupled Higgs (R < 1/2). With the
help of these results, the whole parameter space of the model can be covered by
Higgs boson searches.
