is it possible to change the primary weapon to secondary weapon?
so my character can carry 2 different type of weapon..
i've tried to change the :
<weapon file= base_primary.weapon>into<weapon file= base_secondary.weapon>

and adding it to "faction".secondary.resource
still didn't work though.. any idea guys?

You have to change the "slot" from 0 to 1, 0 being the primary and 1 being the secondary. Take a look at some of the pistol code to see what I'm talking about.