How do I get exim to sustitute a different username?

[Phillip Deackes <gsmh@gmx.net>]

I recently installed Debian 2.1 for a friend. He wanted to be user 'ant'
on his system. His email address, however, is akjohnson@gmx.net.  All
mail sent from his box has 'ant@gmx.net' as his address.

Is there anyway he can get exim to substitute akjohnson for ant? I have
few problems getting domains to show correctly, but haven't had to
change a username before.

Thanks for your help.


--
Phillip Deackes
gsmh@gmx.net
Debian Linux (Potato)