Why won't that happen?
I subscribed to Sling Blue for $20 for the first month. Then with Fox Sports app on ipad, I designate my tv provider as Sling TV and login. Badabing Badaboom.
However, the ipad app is horrible - many, many ads (even with subscription) and not very good navigation to the replays.
I'm watching the games on my Roku (via Fox Sports app because the Roku app is much better then the ipad app and the Roku Sling TV app is very bad).
Wish I could offer more.
NOTE: I just subscribed to Apple Tv, and it looks like a better app on ipad than Fox Sports. Of course, it needs the Sling TV subscription (but you already knew that). It also seems to indicate that a Hulu account would work - but that's probably a Hulu TV subscription. I don't know why you won't be getting the Sling subscription, but that appears to be the way to go. The other option I considered was subscribing to a quality VPN and watching via a UK or German streaming service.