[EXIM] Can exim rewrite Return-receipt headers?

My apologies if this has been discussed before - if so, just point me
to the archive.

We're currently running Exim v1.92 on our mailhubs. Most of our staff
are MS Exchange users who are keen on generating Return-receipt headers
which are of the form <user>@<exchange-machine>.bton.ac.uk . For
outgoing
email we need to rewrite this in the same way as we rewrite From fields,
viz. <A.User>@bton.ac.uk .

Is there any way to do it with Exim - the "h" flag in the rewrite
section doesn't seem to do it.

Cheers,
Dave
---
Dave Lewney  
Unix System Manager             Email:  D.M.Lewney@??? 
University of Brighton          phone:  01273 642669
UK                              fax:    01273 642666

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