[Asterisk-Users] Remote MWI for Central Voicemail?

[Noah Miller]

Hi -

We've got multiple offices with their own asterisk boxes (CVS HEAD  
11/03/04-14:59:37) connecting to each other using IAX forwards.  All  
users are on SIP phones.  Voicemail is centralized to one location.   
Everything is hunky dory except that  the users in the remote offices  
don't get MWI on their phones.  I've seen the other posts to this list  
regarding this, and I've been trying to adapt the SER -> Asterisk  
script that was posted here (uses sipsak):

http://lists.digium.com/pipermail/asterisk-users/2005-February/ 
087929.html

I'm pretty much running the script unmodified, just with my info  
plugged in.  The trouble is I can't seem to get the boxes on the remote  
ends to accept the NOTIFY messages.  They just spit back this:

Mar 25 16:51:39 WARNING[5648]: chan_sip.c:2416 find_call: Call missing  
call ID from 'xxx.xxx.xxx.xxx'

I have Call ID specified in the SIP messages I'm sending like this:

Call-ID: 1234567890@!IP!     (this is unmodified from the script)

I've tried all sorts of combinations here, but I haven't come up with  
one that my * servers will accept/recognize.  Do I need to set up a  
pre-registered sip peer to/from each box to allow these notify messages  
(shouldn't the phone registrations work for this)?  Has anybody gotten  
this script (or any other) to work for remote MWI?  Better yet, does  
anybody know a better way to do MWI over an IAX forward?

Thanks,
Noah