⟩ Can not find PhoneApplicationPage.FullScreen in April CTP?
SystemTray is an attachable property now. You can use it in your page xaml, something like:
<navigation:PhoneApplicationPage x:Class="WindowsPhone.Hello"
xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone.Controls.Navigation"
shell:SystemTray.IsVisible="true">