g4msmail_addReplyTo is used to add a reply to address to an email that will be used with the G4MSMAIL functions.
There is a maximum of 100 reply to addresses allowed.
If you specify a reply to address other than that of the account and you still want the reply to also go to the sender, you will need to also add a reply to address for the sending email address.
Returns: Total number of reply to address for success, -1 for error.
Reply To email address - Specify the Reply To email address
Reply To Name - Specify the reply to name as you would like it to appear on the email
Error Message (output) - Error message