G.711 to T.38 conversion for IP calls on hold with MOH

[VZPRO]

My customer is in the process of upgrading their CS1000 sites to 5.5. For the sites that have already been upgraded, we have been experiencing this problem: A call is placed across the VOIP network from one site A to site B. Site B answers the call and a call trace confirms a G.711 codec. The call is placed on hold and the caller receives MOH. After several minutes, the calling party thinks they get dropped because they no longer hear MOH. A subsequent call trace shows that the codec has changed to T.38 (fax). Customer has re-recorded their MOH (music and messages) because so far, Nortel/Avaya, has said that something in the recording is being interpretted as a fax tone(S). When we Fax tone detection is turned off in the signalling server, this problem does not occur. As soon as it is turned back on, the problem starts happening again. Obviously, the customer needs the ability to fax across their VOIP network as well as the ability to supply MOH and messages. Any thoughts anyone?