Incoming calls disconnect when selecting menu options

I am working on an Asterisk project and have run into a major snag. I am running Asterisk@Home 2.5, the Asterisk version is 1.2.4. I am currently using Broadvoice’s BYOD Lite service for incoming calls during testing. Outgoing calls are going through an H323 trunk to one of my companies existing Gateways.

The problem I am having is with incomming calls. I have a Digital Receptionist configured with five menu items. When I dial 7777 from an X-Lite client logged in as a local Asterisk extension, the DR works fine and all menu items behave the way I want them to. However, when I call in from an external line using the Broadvoice number, I do hear the DR’s voice message but the call disconnects as soon as I press a button to select an option.

If I configure an X-Lite client to log into the Broadvoice account, I can not get a call to disconnect when pressing a button on the external phone.

My server is not behind a NAT device. It is currently behind a PIX firewall in layer 2 mode running version 7.0.4, but I move the server outside the firewall, which had no change in behaviour.

SIP debug output shows that a BYE command was sent as soon as the button was pressed on the external phone.

I have been searching on this issue for days and have found nothing. Hopefully someone on this forum can provide assistance. Thank you in advance.