Ok this is the problem I have,
I run a webserver with 2 domains hosted .. a.com and b.com

both these servers require user registrations and these are sent off
automatically
by a perl script ..

so for one i set "From => registrations@a.com'
and from the other : From => registrations@b.com

These mails are fired off via perl, using the webserver user.

the problem i have, is this, since both are fired off by the same user,

the Return-Path is both cases is webserveruser@a.com given my

myhostname = mail.b.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = b.com
mydestination = localhost.localdomain , localhost.localdomain,
localhost

and all the usual virtual domains with mysql stuff ..

I have dug and dug, and cannot find a way to make the "return-path"
from a.com to be support@a.com and that of
b.com to be support@b.com

any ideas? on how i can get this to work, i know the Return-Path is set
to $sender in sendmail or MAIL FROM
Me specifying a From as part of my mail delivery script, should there
set the Return-Path to the from address right?

This does not happen.

How can i make it work ..