I’m looking into creating a Lead Generation Card: https://blog.twitter.com/2013/capture-user-interest-with-the-lead-generation-card
However I am having problems finding the setting to create the card. According to this article (and others) the setting should be under the advertising drop down: http://blog.hubspot.com/marketing/twitter-introduces-lead-generation-cards-collect-leads
However I don’t see that? Does any have any tips as to how I can set one of these up?