Is there a way to use Stage3D in Flex Mobile projects on iPad?

When I create a project of type "Action Script Mobile Project" the Stage3D works on iPad, Android device and in the AIR desktop simulator.

But when I create a project of type "Flex Mobile Project" it works in the desktop simulator and on Android device but does not work on iPad.

When running on iPad the stage.stage3Ds[] collection is empty.

Is it a sort of limitation made by intent? Or a bug? Or maybe I am doing something wrong?

What I actually need is an ability to render offscreen bitmaps with GPU in an application that uses Spark UI. This is why I need Flex Mobile project.

My configuration is the following:

iPad with retina display

Sony Xperia Tablet Z

AIR SDK 3.7 (and I have also tried AIR SDK 3.8 today)