We have a campaign that is a follow up to phone call discussions/sales calls.  We want to simply add those new contacts to that campaign and then email the follow up to those new users only.  However, when we try and add contacts to that contact list that was used for that campaign, we are unable to "send to new contacts"  Example, in salesforce.com, you can add contacts to a campaign and then "send to those who have not been sent  before"

Are we missing something or does this "basic" functionality not exist?  Currently we are creating a new list and cloning the campaign each day, which is a waste of time and confusing.