Here are the steps to send broadcasts:
First add all the users who will be receiving the broadcast message.
Once subscribers are added launch PCA from the web browser
Log on to PCA.
Select Unity Inbox.
Select New Message tab.
Click on "To" and select "Distribution List"
Check the circle we are set to send the broadcast.
We can select the file from the "message" tab and select the file we want to send.
Sending System Broadcast Messages:
http://cisco.com/en/US/docs/voice_ip_comm/unity/405/administration/guide/ex/sag_0045.html#wp1331441