Frank,
So I am guessing that if you are using a 9 prefix for dialing through the quintum you may be using the intercom prefix settings. Additionally you are using SIP and my concern would be the ability for the intercom settings to work correctly with SIP. I would really need to see the entire config and logs to start to determine what could be happening. I am not as familiar with SIP as I am with H323, but not sure that this is where the problem lies.
MikeM
mike_voip@hotmail.com