"Does this mean if you don't continue to own you don't qualify for it."
I think that is true. You will receive the spin-off dividend, but, because neither the ex-dividend date has been announced, nor has the price split been determined, when you sell USSE, I think you are selling both companies' stock. Somebody quoted the applicable SEC section a long time ago. You'll have to search for it, but it's in these posts, somewhere.
If your USSE stock was in street name, you'll probably never know it happened.
Dino