Web Interface for Remote Administration - how to change SENDER address

As we know there is an option to send critical alerts to an
administrator e-mail address. Neat feature BUT since I have no
dedicated mailserver in client system - nor there will be my only hope
is to use local smtp service.

Web Interface for Remote Administration puts in the sender row machine
netbios name i think. Therefor NO mailserver in the whole world wont
accept the message:(((

Is there a registry key, or some other possibility for me to "fake"
the sender address to something reasonable like [email]somebody@domain.com[/email] so
that mailserver would accept it. I am using friendly ISP mailserver.