Export - CAD Format - Select STEP Files(at bottom) - Click on Options at the bottom of the window - select 242 (top of window) - press OK. I am using Inventor Pro 2016.
Your link is not opening for me. But I did go to the Steptools.com site and had a look. My version of Inventor won't do this. Are you trying to go direct from CAD to CAM? If so, Inventor has never had this capability (at least not in my experience and I have been using Inventor for over 18 years!). Having said that, I do not know if the newest version will do this.
Not sure about getting GD&T from the Step to import. That would be a nice trick. But when you Send a 3d pdf from Annotation tool, you can include the 242 step.