trouble with postfix parameter. ( Was: howto get my email aliases to work?) [SEC=UNCLASSIFIED]

["Paul (NCC/CS.)" <pts%bom.gov.au@localhost>]

Hi my aliases are working but being overridden by this:

in /etc/postfix/mail.cf

myorigin = $mydomain


This ensures return address's in email are:   xyz @ $mydomain
and not xyz @ myhostname.mydomain

Which is good, but the parameter has another effect:

>>>>>
# For the sake of consistency between sender and recipient addresses,
# myorigin also specifies the default domain name that is appended
# to recipient addresses that have no @domain part.
#
#myorigin = $myhostname
myorigin = $mydomain
>>>>>


So mail simply to root ends up being root @ mydomain and therefore
goes to the company sysadmins and servers instead of ME at my box.
(They HATE this).


If I take away this parameter the aliases kick in :

root: pts
operator: pts

and I get roots mail, but without the parameter I have the problem
of return addresses being pts @ host.domainname  !

I need the parameter to specify the return address correctly but it
also effects the SEND address as it says above.

Nightmare!  

Can anyone suggest what I should do ?

thankyou,
Paul.