Actionmailer ignores return-path setting


i have the problem that i want to set the return-path to the envelope
of outgoing emails so bounces can be handled. I tried to set the
header as followed in my mailer class:

def newsletter
subject ‘subject’
reply_to ‘[email protected]
from ‘[email protected]
recipients ‘[email protected]
body :body => ‘content’
headers ‘return-path’ => ‘[email protected]

However, in the outgoing email the return path is automatically set to
[email protected]

I am using Rails 2.3.3 and Postfix 2.3

can anyone point me to the correct setting to set the return-path?