Caller ID calling out remote FreePBX server

I have a FreePBX server on a VM that is the main PBX, and all of our extensions register with this PBX. Due to the nature of the blade server environment we cannot attache hardware cards to the VM. We have Sangoma dual T1 cards in a pair of smaller hardware boxes that act as T1 gateways. Both of these boxes have FreePBX and are trunked to the VM PBX with IAX2 trunks. We need a few of the extensions to send a different Caller ID than the general one set for the DAHDI trunk. The system functions fine passing the calls back and fourth but the extension Caller ID does not override the trunk Caller ID. The do not override box is not checked on the DAHDI trunk on the hardware box. How can I pass the Caller ID from the VM PBX to the hardware PBX over the IAX2 trunk and have it send out the Caller ID entered on the extension entry on the VM PBX. Thanks in advance.