windows phone 8 - prevent showing app screenshot in application navigation in WP8 -

for security critial app need prevent phone making screenshots of embedded browser control.

on windows phone, if hold button pressed, opened applications shown small preview images.

is there way replace image being used there own image. or possible exclude controls using xaml syntax beeing captured?

thanks holger

windows phone 8 gdr 3 introduced hidden property on page object can use prevent screenshots being taken of page. here more detail