document mwi issues for voicemail contexts

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@2561 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configs/zapata.conf.sample

@@ -132,12 +132,24 @@ cancallforward=yes
 ;
 callreturn=yes
 ;
-; Stutter dialtone support: If a mailbox is specified, then when voicemail
-; is received in that mailbox, taking the phone off hook will cause
-; a stutter dialtone instead of a normal one
+; Stutter dialtone support: If a mailbox is specified without a voicemail 
+; context, then when voicemail is received in a mailbox in the default 
+; voicemail context in voicemail.conf, taking the phone off hook will 
+; cause a stutter dialtone instead of a normal one. 
+;
+; If a mailbox is specified *with* a voicemail context, the same will 
+; result if voicemail recieved in mailbox in the specified voicemail 
+; context
+;
+; for default voicemail context, the example below is fine:
 ;
 ;mailbox=1234
 ;
+; for any other voicemail context, the following will produce the 
+; stutter tone:
+;
+;mailbox=1234@context 
+;
 ; Enable echo cancellation 
 ; Use either "yes", "no", or a power of two from 32 to 256 if you wish
 ; to actually set the number of taps of cancellation.