The embedding of the isometry group of the coset spaces SU(1,n)/[U(I)
x SU(n)] in Sp (2n + 2, R) is discussed. Knowledge of such embedding p
rovides a tool for the determination of the holomorphic prepotential c
haracterizing the special geometry of these manifolds and necessary in
the superconformal tensor calculus of N = 2 supergravity. It is demon
strated that there exist certain embeddings for which the homogeneous
prepotential does not exist. Whether a holomorphic function exists or
not, the dependence of the gauge kinetic terms on the scalars characte
rizing these cosets in N = 2 supergravity theory can be determined fro
m the knowledge of the corresponding embedding, a la Gaillard and Zumi
no. Our results are used to study some of the duality symmetries of he
terotic compactifications of orbifolds with Wilson lines.