In-app purchases working in iOS Simulator - but not on device

I am trying to test the In-App Purchases but it seems to be doing something strange...

On my device when I go to activate the purchase nothing happens at all.  So I thought I would test it through the iOS Simulator in Stencyl - when I do this it works correctly-  in that it brings up a dialogue box asking to signing to App Store etc.

Any ideas why this would happen??

Ok that makes no sense, as I was just told over here
http://community.stencyl.com/index.php/topic,52132.0.html
that iOS sim does not allow the IAP to work and that you must test on the device. Did you ever resolve this issue??