can't get In-App-Purchase hosted content to be actually hosted

can't get In-App-Purchase hosted content to be actually hosted

I have an iPad app with In-App Purchase that used to host its content with
Urban Airship (a pox upon their house). Now I'm trying to convert this to
use Apple's hosted content.
I've created a .pkg file for one of my content items, and used Application
Loader (multiple times now) to upload the content. The package passed
validation, I clicked "Deliver," and I watched the progress bar as it was
"Uploading package to the iTunes Store." In the "Hosted Content" tab for
this item, "Host Content with Apple" is clearly checked, and the "Hosted
Content Package:" well shows the standard package icon.
Yet, when I look at the same app on iTunes Connect, and go to In-App
Purchases and view the same content item, it says: "Hosting Content with
Apple: This feature is turned off." (And no hints are provided here as to
how one might turn it on.)
In my code, when I get back the SKProduct from StoreKit, I find that
downloadContentVersion and downloadContentLengths are both nil. And when I
purchase it anyway using a test account, I get a SKPaymentTransaction
whose .downloads is also nil. And if I quit and relaunch Application
Loader, the "Host content with Apple" checkbox is now unchecked. This is
all probably related to the fact that Apple doesn't realize they are now
hosting this content.
Perhaps life is more difficult because this is not a new app or new
content item; both of these were approved long ago, and I'm trying to
update them to the new model. But I certainly don't want to create a new
app just for this. What's the key step I'm missing that makes the Apple
servers actually host this content?