It's on page 10-10 thru 10-12 of the Cisco Unity 3.1(3) System Administration Guide at:
http://www.cisco.com/univercd/cc/td/doc/product/voice/c_unity/unity31/sag/sag313/sag.pdf
Here's the excerpt from the doc:
Using Optional Conversation 1
Cisco Unity Optional Conversation 1 provides an alternative to the standard
conversation messaging menu choices which is the system default. You may
choose to use Optional Conversation 1 because it more closely resembles the
messaging menu choices that subscribers in your organization are familiar with.
When you activate Optional Conversation 1, it is a system-wide change that
applies to all subscribers associated with the Cisco Unity server.
With Optional Conversation 1, some of the touchtone keys that subscribers use to
manage messages by phone are different from those listed in the Cisco Unity User
Guide. However, it does not change the touchtone keys that outside callers and
Cisco Unity subscribers press to send messages. The Cisco Unity at a Glance for
Optional Conversation 1 card illustrates the main Cisco Unity menus available
with Optional Conversation 1. The card is available on Cisco.com at
http://www.cisco.com/univercd/cc/td/doc/product/voice/c_unity/unity31/conv/in
dex.htm.
To activate Optional Conversation 1
Step 1 Start Regedit.
Caution Changing the wrong registry key or entering an incorrect value can cause the
server to malfunction. Before you edit the registry, confirm that you know how
to restore it if a problem occurs. (Refer to the “Restoring” topics in Registry
Editor Help.) Note that a typical backup of the Cisco Unity server does not
back up the registry. Also note that for a Cisco Unity failover system, registry
changes on one Cisco Unity server must be made manually on the other
Cisco Unity server, because registry changes are not replicated. If you have
any questions about changing registry key settings, contact Cisco TAC.
Step 2 If you do not have a current backup of the registry, click Registry > Export
Registry File, and save the registry settings to a file.
Step 3 Expand the key
HKEY_LOCAL_MACHINE\Software\Active Voice\CDE\1.0.
Step 4 Modify the value of the entry SoftKey Config to
C:\CommServer\Support\OptConv1.ini.
C:\CommServer is the default directory in which Cisco Unity is installed. If
Cisco Unity is installed in another directory, use that path instead.
Step 5 Restart the Cisco Unity server.
To reactivate the standard Cisco Unity conversation
Step 1 Start Regedit.
Caution Changing the wrong registry key or entering an incorrect value can cause the
server to malfunction. Before you edit the registry, confirm that you know how
to restore it if a problem occurs. (Refer to the “Restoring” topics in Registry
Editor Help.) Note that a typical backup of the Cisco Unity server does not
back up the registry. Also note that for a Cisco Unity failover system, registry
changes on one Cisco Unity server must be made manually on the other
Cisco Unity server, because registry changes are not replicated. If you have
any questions about changing registry key settings, contact Cisco TAC.
Step 2 If you do not have a current backup of the registry, click Registry > Export
Registry File, and save the registry settings to a file.
Step 3 Expand the key
HKEY_LOCAL_MACHINE\Software\Active Voice\CDE\1.0.
Step 4 Modify the value of the entry SoftKey Config to
C:\CommServer\Support\Unitykey.ini.
C:\CommServer is the default directory in which Cisco Unity is installed. If
Cisco Unity is installed in another directory, use that path instead.
Step 5 Restart the Cisco Unity server.
