[Exim] aliasfile director

hoi!

what can i do if i want to use aliasfile with include domains but
without users?

virtuser_aliases:
driver = aliasfile
search_type = lsearch
include_domain = true
file = /etc/mail/virtusertable
user = root
file_transport = address_file
pipe_transport = address_pipe

here i can use uin@??? in virtusertable. but i cannot use
*@host.tld.... why?

manoo