The first step is to install the Unified Messaging role. This procedure assumes that the Exchange 2010 server has already been installed. To add the Unified Messaging server role, complete the following steps:
1. In Control Panel, select Add or Remove Programs.
2. Select Microsoft Exchange Server 2010.
3. Click the Change button to enter Exchange Maintenance mode.
4. Click Next.
5. Select the Unified Messaging Role check box, as shown in Figure 20.9, and click Next.
6. After the installer conducts readiness checks, click the Install button ...