smail misconfigured?

["Markus Reuscher" <markus@www.htu.tuwien.ac.at>]

Hi all!

I want to receive mails on my server with the addresse
eg markus@htu.at

This is a cut from my smail/config:
------------------------------------------------- 
visible_name=www.htu.tuwien.ac.at
more_hostnames=localhost
-domains
hostnames=www.htu.tuwien.ac.at:htu.at:www.htu.at
------------------------------------------------- 

When I send mails to markus@htu.at I get this
reply:

   ----- Transcript of session follows -----
... while talking to ns.node.at.:
>>> RCPT To:<markus@htu.at>
<<< 550 <markus@htu.at>... User unknown
550 <markus@htu.at>... User unknown
-------------------------------------------------

'markus' exists as user on this machine. What must I
write in the config file to be able to receive mails
on all 3 domain names?

Many thanks
Markus