mail() Return-Path: doesn't

[Anon]

I'm using the following script:-

mail("$toAddress", "Subject", $message, "From: Andrew Parry <[e-mail]>\n" .
"Reply-to: Andrew Parry <[e-mail]>\n" .
"Return-Path: [e-mail]");

Works fine except for Return-Path: which doesn't return bounced mail to the specified address.

Any ideas?

Regards,
Andrew