qmail + vpopmail: Need direction on auto mail on account creation

System: Centos 5.7
Environment: qmail, vpopmail, squirrelmail, php, apache

Hi,

I need direction on how to setup qmail to send auto-generated email upon email account creation.

For example once an account is created (usually web-based), an email is sent to that account from administrator, etc. welcoming the user or provide warning or precautions.

Thanks :)