Hi there,
Just to add a note to the great tips from Deepak (+5), as you both noted these changes will only apply to newly created users as template changes are not retroactive. So you may want to use Bulk edit to change all the existing users;
Here's a clip;
To Edit User Account Information in Bulk Edit Mode (some editing from original)
Step 1 
In Cisco Unity Connection Administration, on the Search Users page, check the applicable user check boxes, and select Bulk Edit.
If the user accounts that you want to edit in bulk do not all appear on one Search page, check all applicable check boxes on the first page, then go to the next page and check all applicable check boxes, and so on, until you have selected all applicable users. Then select Bulk Edit.
Step 2 On the Edit Conversation>Flex Stack page, change settings as applicable.
Note The Status message at the top of the Edit Conversation page tells you how many user accounts are being edited. Also note that the page is populated only with the fields that you are allowed to edit in bulk mode, and that the fields available for edit also depend on whether all of the user accounts reside on the local server.
Step 3 If applicable, set the Bulk Edit Task Scheduling Fields to schedule the Bulk Edit operation for a later date and/or time.
Step 4 Select Submit.
Step 5 If applicable, continue to change settings for these user accounts on the related pages available from the Edit menu. As you make changes on each page, select Submit before going on to the next page to make additional changes.
Try a couple of test users first to come up with the exact plan.
Cheers!
Rob
