Add this at the beginning of your activity (requires JavaObject library)
Dim J As JavaObject = Activity
J.RunMethod("setPivotX",Array(0.5f*Activity.Width))
J.RunMethod("setRotationY",Array(180.0f))
It won't mirror the activity title (in case you have it)
Will work with most normal views, but not tested 'deeply'
--EDIT--
It will work correctly with buttons, labels, panels, imageviews,.... but not with messageBoxes, toastmessages and inputLists... I guess that other dialogs will also fail to mirror
In general, it won't work with views that are not added directly to the Activity but to the Window Manager. Still, it can be useful if you need no interaction and can control the type of views that will be shown to the driver.