Select your outgoing e-mail address in Identity Manager. Your outbound e-mail address will display this address on the "From:" line, along with your display name.
Go to Identity Manager and login with your IdentiKey.
To select an alternate, click on the Outgoing E-mail Address: drop-down menu and choose the address you prefer.
If this is the only change you plan on making, click on the Save button at the bottom of the page. Then click OK to return to the main menu.