I'm selling an OS X app on the Mac App Store which due to its intended purpose is useful in Germany only. Consequently, it isn't localized but available solely in German language: It doesn't employ Base localization and its Info.plist's CFBundleDevelopmentRegion key is set to German. On the Mac App Store it's correctly displayed as being available in German language only.
I have recently added In-App Purchase functionality to this app. It works fine but there is a major issue regarding localization: Whenever an user is trying to make an In-App Purchase, StoreKit displays a misleading message text insisting that the user is logged in to the wrong store and needs to switch to the German store because the In-App Purchase item is only available in the German store. Naturally, this scares away potential German customers as they of course are already logged in to the German store and the message that is displayed nevertheless makes no sense to them. Furthermore, the selling price of the purchase is displayed using the wrong currency ($ instead of €) because StoreKit somehow doesn't honor the user's App Store region affiliation.1
This feels like a bug in StoreKit / iTunes Connect, but Apple hasn't shown to be helpful in investigating the issue so far. My question therefore is:
How does StoreKit determine which region's App Store it should query for available In-App purchases? And why does it think it's logged in to the wrong store in the first place?
Is there a way I can make my app try to access the German store only in order to circumvent this StoreKit quirk? I'm thankful for any hint!
1 I'm making use of SKProduct's priceLocale property of course - this is not the cause of the issue.