First, thanks for your answer,
For your third point: how can I use GnutellaApplication for GIA or
Gnutella0.6 overlays? As far as I understood, GnutellaApplication can
be used in the simulation of Gnutella0.4, so not for GIA nor for
Gnutella0.6. It is essential for me to perform some traffic (even the
very same traffic) over these overlays in order to have a reasonable
comparison between the overlays.