how to make wildcard subdomains point to main domain

[cham74]

I need to have wildcard subdomains and I see that in the ispcp.conf file domain aliases have wildcard *.mydomain.tld

however when I ping testing.mydomain.tld
returns ping: unknown host testing.mydomain.tld

I manually added

*.mydomain.tld. IN A x.xxx.xxx.xx

Where is the ip is the same as the http://www.mydomain.tld

to /etc/ispcp/bind/working/mydomain.tld.db

and ran sudo /etc/init.d/bind9 restart

Using the interface to set up a subdomain works fine, creating a folder, but I don't need that, I want to point the subdomains to the main domain. As per this thread http://groups.drupal.org/node/16862#debian

This thread suggests the same configurration, http://steinsoft.net/index.php?site=prog...carddomain

Any suggestions why it is not working and what I am doing wrong. Thanks