server message from drupal are <user>@<box>.bluehost.com

Hey,

I am trying to configure one of my sites running drupal (which is an addon domain to my account at Bluehost.com) so that when user gets a system message from drupal, the return address is info@.com ... but every message the server sends resorts to my username@box***.bluehost.com.

I've had a look in the knowledgebase and can't seem to figure out why this is happening. The admin/server email is configured in drupal as info@.com, and I have created a mailbox for that email in my cpanel, yet it still doesn't send from that address.

Any ideas would be much appreciated!