[asterisk-users] How to change sendmail return path

[shadowym]

Is there a way to change the return path sendmail uses when sending out
voicemail to email?

Currently the voicemails my asterisk system emails out have a return path of
"asterisk at mydomain.com"
I would like the return path to be "noreply at mydomain.com"

I cannot find any place where I can change that.  

I tried adding a sendmail alias to send "asterisk" to "noreply" and even
tried "root"
There are no config options anywhere in any asterisk *.conf or *.inc file
which affect this
There is nothing in my etc/hosts file which would cause the "asterisk".

I'm running CentOS 5.1, Asterisk 1.4.15, FreePBX 2.3.1