  The transition form factor for electrodisintegration of a two-body bound
system is calculated in the Bethe-Salpeter framework. For the initial (bound)
and the final (scattering) states, we use our solutions of the Bethe-Salpeter
equation in Minkowski space which were first obtained recently. The gauge
invariance, which manifests itself in the conservation of the transition
electromagnetic current Jq = 0, is studied numerically. It results from a
cancellation between the plane wave and the final state interaction
contributions. This cancellation takes place only if the initial bound state BS
amplitude, the final scattering state and the operator of electromagnetic
current are strictly consistent with each other, that is if they are found in
the same dynamical framework. A reliable result for the transition form factor
can be obtained in this case only.
