It's easy to change the address it appears that the email messages sent from Email Center Pro are coming from. This is changed using the Send Email As setting within the Mailbox setup in Accounts & Tools:
Send Email As
Type the name associated with the "Mailbox Email Address" listed above. This might be a person, department, or project name.
NOTE: This name will appear as the "from" name on all outgoing email you send to your contacts. You'll want to make sure users can readily identify the sender (Your Company Sales).
Type the email address as it will appear to be sent from. This can be the same as the 'Mailbox Email Address' name, or an outside email address that has been linked to this mailbox.
NOTE: Contacts will see this email address as the sending mailbox (firstname.lastname@example.org, etc.) on all outgoing mail, and replies will go to that email address. For you to receive these replies, you MUST make sure that email address redirects to the selected mailbox.
Remember, if you're changing the Send Email As settings you should take some additional steps to ensure that your email messages aren't detected as spam: