Nope, that's not possible.
You have to disable signature check in services.jar (SUPERUSER MOD) because system is always checking your themes(apps) keys.
We don't have those keys to sign our apps, only Sony has them, so we must disable/delete that part of code in services.jar. / Patching services.jar
To do that you have to be able to change your system files - you need administrative rights or in one work root.
Sent from my C6903 using Tapatalk