Three party conference voice problem

[Mils]

Hi all,

I have an OXE R11.1 installed on the main office and i have IP Phones (IP Touch 4018) installed on the network.
Phones in the office are directly connected to the Alcatel switch OS6450-24 and the phones installed in the remote sites are connected on POE Packetcom switches and brought to the PABX through an OSPF and RSTP network.
The configuration is made on all the network and phones can call each others without any problems.
The only problem is in conference.
When i make a conference between 3 phones in the main building (directly connected to the alcatel switch) it works perfectly.
But when i try to make a conference with a remote site, i can hear him (i am in the main office) but he can not and i can hear/talk my third colleague who are also in the main office.
Knowing that a simple call between me and him (remote site) works.
And a three party conference between 3 remote phones does not work too.

It seems to be a gateway problem but i could not find the issue as

Thank you for your help

[haroun]

hummmm
direct rtp betwen iPhones when regular call is made, but if there is a confrence other resources are used like GD OR INITIP3 , did you manger domain for remote users?