Couple problems here.
1. Customizing the message content is not possible.
2. the 729a codec is not free for distribution - it's to be installed on the Unity box and is installed with the MediaMaster control (i.e. we're licensed to use it with VMO). It's not legal to install it on machines not running VMO I don't believe - you'd better check the license agreement on that count. Pretty sure offering links to anyone on any machine to install it is not covered. This is a 3rd party codec that we're licensed to use on machines that have one of our licensed clients on them (i.e. VMO).