Setting the subscribe value and the voicemail server to
XXXX@voxalot.com didn't work, but changing the voicemail server $USER@us.voxalot.com did the trick.
Just left myself a voicemail, deleted it from the web, a few minutes later the MWI kicked in and my vm indicator turned off. Hopefully it wasn't a fluke, but looks like it's working. Thanks guys.