  The long standing problem of neutron-proton pairing correlations is revisited
by employing the Hartree-Fock-Bogoliubov formalism with neutron-proton mixing
in both the particle-hole and particle-hole channels. We compare numerical
calculations performed within this method with an exact pairing model based on
the $SO(8)$ algebra. The neutron-proton mixing is included in our calculations
by performing rotations in the isospin space using the isocranking technique.
