Announce mail returned/bounced mails do not go to returnpath

[pentacle]

Great script, everything works fine but why do send emails that are bounced or user has ended account not returned to the returnpath. I've been told
that the php function mail has a 5th parameter and when you use switch -f and returnpath email behind it solves the problem. How do I implement this
in the index.php(admin) script on the right way?

[PHPWebScripts]

Please email me, I will add it there and send you the edited file. It's not there by default as it doesn't work on all servers. Also mail servers usually add it there automatically.