Hello,
When you are using login credentials, like equitrac, and you want the Xerox to use the multifunction from address you need to turn off the personalization option (Screen Shot Attached).
However If you turn off personalization your scan to home will no longer work, so if you are doing scan to home then the option you are looking for is not available.
The second option you are asking about to have the reply go to someone other than the sender is not available and to my knowledge can't be done as when you hit reply from any email program it just picks up the senders address.
regards,
James