I am testing the ability of Cisco Unity Connection 8.5 to provide MWI to Avaya phones. My setup is as follows:
 
Avaya IP phone hung off of Avaya CM version 6.0
SIP trunk from Avaya CM to CUCMSME 8.5
SIP trunk from CUCMSME to CUCM 8.5
Unity connection 8.5 integrated via SCCP ports to CUCM
 
The calls route without any issue and I can leave a voicemail on Unity Connection for the Avaya phone. When the Unity sends the SIP message to light the Avaya phone, the Avaya rejects it. I can get Avaya Modular Messaging to light a Cisco phone via the same setup. The only difference in the SIP messages from Modular Messaging as opposed to Unity is the blue portion:
 
Messages-Waiting: yes
Message-Account: sip:5555555@domain.com
 
Is there any way to build a script that attaches that line to a message when there is a message waiting only? Other than that there are no scripts in use between the Avaya and Cisco PBX systems.
 
Jeremy