I am going to try and set up TMDA to work with Zimbra as it will be a MUST if we want to make this move.

Part of the TMDA Instruction states:
MTA Configuration (Postfix)

1. Enable the recipient_delimiter parameter in Postfix's main.cf if it isn't already. Make sure the character you choose matches RECIPIENT_DELIMITER in your ~/.tmda/config.

I cannot find this RECIPIENT_DELIMITER line the the Postfix main.cf.

Can I add it?