To make the message waiting indicator work (on a Yealink phone, or maybe any phone) with Asterisk 1.6 and FreePBX 2.7 you need to modify the voicemail.conf in /etc/asterisk to:
pollmailboxes=yes
pollfreq=5
Cheers
Daniel
via: http://danielaliaman.com/blog/

We are happy to present the latest script which incorporates both Asterisks versions. The script does ask what Asterisk version you wish to install of course.
This script was tested on Debian Lenny 5.0x.
Enjoy and as usual your feedback is greatly appreciated.
Thanks
Intuit Team.
Script found here (right click save as): http://210.5.42.12/downloads/asterisk/asterisk-1-install

We are publishing the latest Asterisk install that will setup basically Asterisk 1.6.20 and 1.4.28 respectively. It is designed to be a single command line execution where you key in your MySQL password when you run the script and it will install everything in about 30 minutes with 200kbps download speed.
It has multiple tools via [...]

If you run FreePBX and Asterisk 1.6 and tried to execute “amportal stop” the script might throw an exception and treat that Asterisk is not running and attempts to restart or some weird stuff keep happening.
The issue is caused by the freepbx_engine script which amportal calls that has a depreciated command for stopping Asterisk called [...]