Vaction with whole domain

[Rene Marticke]

Hi,

I have a domain wich should be used anymore but some people ignore this 
and send mails to the old adresses.
Now i tried the following setup :

/kolab/etc/postfix/virtual
@my.old.domain olddomain at groupware.local

Now i tried to setup a vaction message.
Here is the problem.
I have to enter all adresses in to field. But i don't know them all 
because there is also a catch all.

Can you tell me a way pls how i can setup a vaction text for the whole 
domain.

tnx
best rene