You don't change this setting from the internet services but by entering the config at the devices touchscreen.
Logon as admin, press the machine status button, move to the Tools tab, Service Settings, Embedded fax.
From there on, you'll find someting like outgoing faxes default (here it's in Dutch, so I don't know the exact English translation), where you'll find the fax confirmation setting. By default it's set that it only prints a confirmation sheet upon failure.
