Here's what I have found so far...
Centralized IPO system where the voicemail system resides, if a call from a Cisco phone to a user here, the voicemail answers and the Cisco user hears the greeting and can leave a message.
If however, a Cisco user dials a user at a remote IPO system, the call eventually routes to voicemail (verified through SSA) but the Cisco user keeps hearing ringback.
The setup is this...
Central Site IPO has a 10-channel SIP trunk to the Cisco CM and a SCN setup (H.323) IP trunks to the remote IPOs.
All of the remote IPOs only have H.323 trunks to the central IPO.
Running version 5.0.26 on the IPO systems.
The work around...
Created a user on the central site that is unconditionally forwarded to a system short code then to a vm node to get an automated attendant. The Cisco user then can dial an extension on a remote IPO and get that user's greeting if unanswered.
Here is a look at the scenario before setting up the work around...
Trace Output - All Channels:
4/16/12 8:44:15 AM-748ms Line = 17, Channel = 1, SIP Message = Response, Direction = From Switch, From = 8888@192.168.222.1, To = 1025@10.0.0.38, Response = 100 Trying
4/16/12 8:44:15 AM-749ms Line = 17, Channel = 1, SIP Message = Invite, Direction = To Switch, From = 8888@192.168.222.1, To = 1025@10.0.0.38
4/16/12 8:44:15 AM-761ms Call Ref = 1477, Originator State = Dialling, Type = Trunk, Destination State = Seized, Type = Target List
4/16/12 8:44:15 AM-770ms Line = 110, Channel = 1, Line Ref = 11403, Q.931 Message = Setup, Call Ref = 1477, Direction = From Switch, Calling Party Number = 88881921682221, Called Party Number = 1025
4/16/12 8:44:15 AM-834ms Line = 110, Channel = 1, Q.931 Message = CallProceeding, Call Ref = 1477, Direction = To Switch
4/16/12 8:44:15 AM-837ms Call Ref = 1477, Originator State = Dialling, Type = Trunk, Destination State = Dialling, Type = Trunk
4/16/12 8:44:15 AM-897ms Line = 110, Channel = 1, Q.931 Message = Alerting, Call Ref = 1477, Direction = To Switch
4/16/12 8:44:15 AM-899ms Call Ref = 1477, Alerting, Line = 110, Channel = 1
4/16/12 8:44:15 AM-900ms Call Ref = 1477, Originator State = Incoming Alerting, Type = Trunk, Destination State = Outgoing Alerting, Type = Trunk
4/16/12 8:44:15 AM-902ms Line = 17, Channel = 1, SIP Message = Response, Call Ref = 1477, Direction = From Switch, From = 8888@192.168.222.1, To = 1025@10.0.0.38, Response = 180 Ringing
4/16/12 8:44:31 AM-008ms Line = 110, Channel = 1, Q.931 Message = Connect, Call Ref = 1477, Direction = To Switch
4/16/12 8:44:31 AM-174ms Call Ref = 1477, Originator State = Connected, Type = Trunk, Destination State = Connected, Type = Mailbox
4/16/12 8:44:38 AM-806ms Line = 17, Channel = 1, SIP Message = Cancel, Call Ref = 1477, Direction = To Switch, From = 8888@192.168.222.1, To = 1025@10.0.0.38
4/16/12 8:44:38 AM-809ms Line = 17, Channel = 1, SIP Message = Response, Call Ref = 1477, Direction = From Switch, From = 8888@192.168.222.1, To = 1025@10.0.0.38, Response = 487 Request Terminated
4/16/12 8:44:38 AM-810ms Call Ref = 1477, Originator State = Clearing, Type = Trunk, Destination State = Connected, Type = Mailbox
4/16/12 8:44:38 AM-810ms Call Ref = 1477, Disconnect from Originator End
4/16/12 8:45:27 AM-221ms Line = 17, Channel = 1, SIP Message = Response, Direction = From Switch, From = 8888@192.168.222.1, To = 1103@10.0.0.38, Response = 100 Trying
4/16/12 8:45:27 AM-222ms Line = 17, Channel = 1, SIP Message = Invite, Direction = To Switch, From = 8888@192.168.222.1, To = 1103@10.0.0.38
4/16/12 8:45:27 AM-237ms Line = 17, Channel = 1, SIP Message = Response, Call Ref = 1486, Direction = From Switch, From = 8888@192.168.222.1, To = 1103@10.0.0.38, Response = 180 Ringing
4/16/12 8:45:27 AM-238ms Call Ref = 1486, Originator State = Incoming Alerting, Type = Trunk, Destination State = Alerting, Type = Target List
4/16/12 8:45:33 AM-243ms Call Ref = 1486, Originator State = Incoming Alerting, Type = Trunk, Destination State = Alerting, Type = Mailbox
4/16/12 8:45:33 AM-248ms Line = 17, Channel = 1, SIP Message = Response, Call Ref = 1486, Direction = From Switch, From = 8888@192.168.222.1, To = 1103@10.0.0.38, Response = 200 Ok
4/16/12 8:45:33 AM-258ms Line = 17, Channel = 1, SIP Message = Ack, Call Ref = 1486, Direction = To Switch, From = 8888@192.168.222.1, To = 1103@10.0.0.38
4/16/12 8:45:33 AM-261ms Call Ref = 1486, Originator State = Connected, Type = Trunk, Destination State = Connected, Type = Mailbox
4/16/12 8:45:33 AM-261ms Call Ref = 1486, Answered, Mailbox #Pat Lane
4/16/12 8:45:38 AM-238ms Line = 17, Channel = 1, SIP Message = Bye, Call Ref = 1486, Direction = To Switch, From = 8888@192.168.222.1, To = 1103@10.0.0.38
4/16/12 8:45:38 AM-240ms Line = 17, Channel = 1, SIP Message = Response, Call Ref = 1486, Direction = From Switch, From = 8888@192.168.222.1, To = 1103@10.0.0.38, Response = 200 Ok
4/16/12 8:45:38 AM-241ms Call Ref = 1486, Originator State = Clearing, Type = Trunk, Destination State = Connected, Type = Mailbox
4/16/12 8:45:38 AM-241ms Call Ref = 1486, Disconnect from Originator End
If you notice on the first call from the Cisco user to ext. 1025 (remote IPO) there is no response 200 (for answered) so the Cisco never gets a greeting
On the second call to ext. 1103 (local on the central IPO) there is a 200 response that shows the call answered and the Cisco user actually hears the 1103 greeting.
Hence, the work around through the automated attendant because I don't know what else to do with it.