In order to set your Interspire Email Marketing Software to send mail from your dedicated IP address instead of the main ip of the server you must do the following.
Edit this file in your email marketing softwares file:
Find this line:
var $_sendmailparameters = null;
And change it to:
var $_sendmailparameters = "-f bounce@YOURDOMAIN.COM";
Note: You should use whatever email address you setup as your bounce collector.