[Exim] Alias file help

Hi,

I am trying to set up exim to send any mail sent to an unknown address
(eg. not a user and not an alias) to one of the accounts...

In the exim.conf I have changed search=lsearch to search=lsearch* for
the alias file directive.

and on the last line of the aliases file I added *: username

Now all mail comes to that username even if i send it to a known
username or to one of the addresses in the aliases file...

Is there something else I have to do in order to get this working?

Thanks