  The modifications induced in the calculation of the cross section of the
diffractive process gamma gamma -> J/Psi J/Psi when the gluon propagator is
changed are analyzed. Instead of the usual perturbative gluon propagator,
alternative forms obtained using non-perturbative methods like Dyson-Schwinger
equations are used to consider in a more consistent way the contributions of
the infrared region. The result shows a reduction in the differential
cross-section for low momentum transfer once compared with the perturbative
result, to be confirmed with future experimental results from TESLA.
