Android : Android In-App Billing can't query

I created a signed APK and uploaded it to PlayStore into a beta channel. It is not published, but my in-app items are active.

Now, I run iaphelper.queryInventoryAsync() with my sku-Array, but I don't get data back, except of the item android.test.purchased.

Where can I look to see, why my items are invisible? All my items are managed and my user is an tester, and not the developer-account.