  We discuss and explore new aspects of the generalized Dyson mapping of
nuclear collective superalgebras composed of an arbitrary fermion-pair algebra
and a set of single-fermion creation/annihilation operators. It is shown that a
direct consequence of the particular mapping procedure is the conservation of
the total number of ideal particles in the resulting boson-fermion system. This
provides a microscopic framework for the phenomenological supersymmetric models
based on the U(6/2Omega) dynamical superalgebras. Attention is paid to the
mapping of single-fermion creation and annihilation operators whose detailed
form cannot be determined on the phenomenological level. We derive the general
expansion of the single-fermion images that result from the similarity
transformation employed to ensure non-redundant bosonisation in the ideal
space. The method is then illustrated in an application to the SO(4) collective
algebra, a natural extension of the SU(2) seniority model.
