RT cannot receive emails from outlook

I apologize if this was asked already. I’ve been working on RT for awhile and cannot get my head wrapped around how to properly get RT to receive emails from Outlook to either create or comment on tickets.

I’m using:
Set($MailCommand, “sendmail”);
Set( $SendmailPath, ‘/usr/sbin/sendmail’ );
rt: "|/etc/smrsh --queue detection --action correspond --url http://my_rt_instance
rt-comment: "|/etc/smrsh --queue detection --action comment --url http://my_rt_instance

I’m able to have RT send emails when creating a ticket, but on reply nothing happens.

Thanks in Advanced,