BCM 450 outgoing calls are not recognized by auto attendants-DTMF issue?

[CSSIowa]

I have a BCM 450 that is on the same campus LAN as three BCM 50's. All calls go out through one of the BCM 50's on PRI (VOIP between all switches). All systems can make calls inside or outside the local network. Any outgoing calls on those BCM 50's will navigate any auto attendant we have found, but the BCM 450 won't. Customer hears outgoing tones but AA does not respond, ever. Most you get is a replay of the menu. CDR says that the 450 is sending the digits, but the gateway BCM 50 is only receiving outgoing call digits, no AA navigation digits (just outgoing call digits). The digits outpulsed for AA navigation are audible at the far end, but I believe they are being received by the Gateway BCM50 as audio (not DTMF data). We tried to force the system to G711 protocol, no fix. We tried long tones, no fix. Got the network guys to look for lost packages, they found and fixed some minor issues, no fix. Absolutely no known problems with voice quality, or other routing issues. Pulling my hair out....will get system software and feature code info tomorrow. Help!