  The phase ``jumps'' for solitons interacting on a vortex filament, observed
in experiments, have been unaccounted for since more than twenty years. Using
explicit formulas describing the interaction of two solitons on a thin vortex
filament in the Localized Induction Approximation we show that an appropriate
choice of the parameters of the solitons leads to large phase shifts. This
result does not depend on the axial flow along the filament.
