  The zero-range potential approach is extended for the description of
situations where two-body scattering is resonant in arbitrary partial waves.
The formalism generalizes the Fermi pseudopotential which can be used only for
s-wave broad resonances. In a given channel, the interaction is described
either in terms of a contact condition on the wave function or with a family of
pseudopotentials. We show that it is necessary to introduce a regularized
scalar product for wave functions obtained in the zero-range potential
formalism (except for the Fermi pseudopotential). This metrics shows that the
geometry of these Hilbert spaces depends crucially on the interaction.
