I changed OpenIabHelper to only select AmazonAppstore as the store if the installer package name is com.amazon.venezia.

Testing upon uploading to the Amazon app store gave me this raw stacktrace:

java.lang.NullPointerException
at org.onepf.oms.appstore.AmazonAppstoreBillingService.onPurchaseUpdatesResponse(AmazonAppstoreBillingService.java:238)
at com.amazon.inapp.purchasing.KiwiPurchaseUpdatesCommandTask$1.run(Unknown Source)
at android.os.Handler.handleCallback(Handler.java:605)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4558)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
at dalvik.system.NativeStart.main(Native Method)