Sending voicemail by email - Server configuration

I am having some difficulty finding instructions on how to configure the email feature for voicemail. What I want to do is use an existing e-mail server (Exchange) to send the mail but I can’t find any information on how to configure this. I don’t want to use the Linux box as the email server, I already have one on the network so I’d rather use it.

Seems to me that I need to identify the SMTP host name, user name and password so that Asterisk can send the email but I haven’t found anything documented, including the voicemail.conf file that tells me how to do this. Everything seems to point to using the email server on “localhost”.

Seems to me that setting a server host name, UID and PWD would be pretty standard but I am coming up empty. Can someone help me out?