You will need to modify the named config for your domain..
its located in /home/dns/var/named
edit db.myvirtualdomain.xxx and at the end put the following:
* IN A xxx.xxx.xxx.xxx
where xxx.xxx.xxx.xxx is the IP address that you want *.myvirtualdomain.xxx to go ... then issue a restart of bind..
/etc/rc.d/init.d/named restart
and you should now be able to ping anything.myvirtualdomain.xxx and have it sent to the IP address you specified.
After it works like you want, you will want to modify the template file as well... (I'm not exactly sure where it is for this file..)