  We reanalyze the recent computation of the amplitude of the Higgs boson decay
into two photons presented by Gastmans et al.. The reasons for which this
result cannot be the correct one have been discussed in some recent papers. We
address here the general issue of the indeterminacy of integrals with
four-dimensional gauge-breaking regulators and to which extent it might
eventually be solved by imposing physical constraints. Imposing gauge
invariance as the last step upon R_xi gauge calculations with four-dimensional
gauge-breaking regulators, allows indeed to recover the well known H -> gamma
gamma result. However we show that in the particular case of the unitary gauge,
the indeterminacy cannot be tackled in this same way. The combination of
unitary gauge with a cutoff regularization scheme turns out to be
non-predictive.
