Question : How can i change the default Reply To address in Outlook on Exchange.

In our company we want to change the mailflow to our developers (7 in total). All mails should be received by the [email protected] mail-address. Developers should still be able to receive internal e-mails, they also must be able to send external e-mail, but the sending address should be [email protected].

We wanted to do this as follows.
In the Users & Computers MMC we want to remove the [email protected] address, set the [email protected] as the default SMTP-address. This way the developers can still comunicate with everyone in the company. The next step is to set the smtp-addrress [email protected] as an extra SMTP-address for [email protected]
With this situation we can let all developers mail internally, and all mail sent to them is received by the planner, (who then redirects the mails if necessary).
On the clientside (Outlook 2003) we wanted to set the "Send reply-to address = [email protected]. But this option is not available in Outlook when connected to exchange, dropping them to pop/smtp ect is not an option.
Also instructing the developers to manually keep changing the MAIL FROM (Send on behalf) will most probably not work, the chance that it will sometimes be forgotten will be too big.

Research on the net didn't yet produce an answer,

Clients run XP and Outlook 2003. (Outlook 2007 is available if needed). Servers all run  Windows 2003, Exchange is 2003 with SP2.  

Answer : How can i change the default Reply To address in Outlook on Exchange.

How about creating a "[email protected]" mailbox that all 7 of your users have access to?  They would open that mailbox as their primary mailbox, but also have Outlook open their individual mailboxes as additional mailboxes.  They would then see emails for both, be able to send from "planner" by default, can choose to send from their own, by specifying the Send As with their own name, and have a single repository for messages sent to "planner".