Hi.
My server didn't have this problem when i came across this thread so i had time to investigate a bit. I had a voicemail.xml file in /etc/freeswitch/languages/*/vm/ but it was an older one than in /var/www/fusionpbx/resources/templates/conf/languages/*/vm.
The first thing i did was to run the php upgrade command mark listed earlier in this thread. This broke the voicemail prompts for me. Next i deleted the old voicemail.xml file and re ran the php upgrade command. Things now work as expected with the new option added. BTW, let me just say adding this option was a great idea. I spent some time last week reading the code to understand how the voicemail ivr worked in preparation to make some changes to it myself, This was one of the changes i wished for, now i don't have to do this one.
Now, with that having been said, here is what bugs me. It doesn't look to me like the code was written to account for an already existing voicemail.xml file in /etc/freeswitch/languages/*/vm which means people who upgraded at a certain point will all have broken systems and the only way to fix this is to remove the outdated file. Removing/replacing the file itself is easy enough to do. The real issue, at least in my mind is no form of public release notes that hinted at this change before it was reported as a problem. If i'm wrong and said notes exist, could someone point them out to me?