default from address (maybe ['hooks']['from'])

[Liam Hoekenga]

I'd like to find display the default from address in the message window's from 
line (like it does when you actually define the an email address in your 
default identity)..

so if someone hasn't edited their default identity it would read:

    $imp['user']@$imp['maildomain'] (Default Identity)

instead of merely:

    (Default Identity)

I've played around with the ['hooks']['from'] but that only seems to change the 
outgoing address when the message is sent.. not when the composition window is 
displayed.

Apparently both our users and our helpdesk is confused by it only saying 
"Default Identity").  The alternative suggestion was to some how populate the 
default identity automatically, but I think that doing the former would be 
easier.

Any suggestions? 

Liam