Drupal 6 Multisite on Bluehost

I have a drupal install running at www.firstdomain.com, which is hosted on bluehost. I am trying to add a domain www.seconddomain.com to the same firstdomain bluehost account and thus run two different domains, all under drupal. I follow the instructions for multisite drupal installation here: http://www.webhostingclue.com/webmaster-tutorials/web-design/344-how-to-... and even here: http://drupal.org/node/368484, but when I do the symlink step what I get is that www.seconddomain.com looks exactly like www.firstdomain.com, and what I want is that www.seconddomain.com is a completely different website. Any ideas what I am doing wrong?

If I try going www.seconddomain.com/install.php, I get a message that drupal is already installed. So I don't get it. I have drupal on public_html, one site at public_html/sites/firstdomain, and I created a directory public_html/sites/seconddomain with the appropriate separate database. I then set up the seconddomain as an add on domain with cpanel, which creates a directory public_html/seconddomain. I then delete public_html/seconddomain and create a symlink to point public_html/seconddomain to public_html . Now I navigate www.seconddomain.com and it looks exactly like if I had just navigated to www.firstdomain.com

Please help!