Deliver Messages to both Forwarding Address and Mailbox problem

[pwinstanley]

I have a two-exchange server environment, FE/BE configuration. If I set up a user in ADUC with Delivery options set to forward to an outside email address AND the checkbox set to Deliver Messages to both Forwarding Address and Mailbox then that user will recieve TWO copies of a piece of mail in his forwarded account. The conditions have to be that the forwarding address is an outside email (i.e. a Contact set up with a outside SMTP address) and the checkbox is checked for the outside account to receive duplicate mails. If I set it to another AD user then the mail only is recieved once.

After checking on the web someone states this 'What is happening is that the Front End server sees the rule and sends the mail tot he Alternate Recipient and then sends the mail to the Back End and when it gets there this Server does the same thing.' but doesn't give the solution.

Does anyone out there know?

Thanks
P