[Freeswitch-users] CALL-ID

HI, I need a little help. I have opensips and behind opensips a hew few Freeswitch servers which are for media handling. Opensips is also doing acc with radius. Here is what is happening and I do not know how can I prevent FS do doing so: A CALLS B. A(call-id)->Opensips(call-id)->fs(call-id)->opensips(fs change call-id!!!)->B(changed call-id). How to prevert so that FS will not change call-id of the call? thx! miha