How can I customize lock screen push notifications on MetroPCS Samsung Avant running Android 4.4.2

[AC Question]

I have installed a messaging app which I would like to use in conjunction with the default SMS messenger on the phone. When I receive a message on the 3rd party application (TextSecure) I get a sound notification and a notification bubble on the app icon but no push notification on my lock screen like I do when receiving an SMS.

My friend is running Android 5.2.1 on his phone and he does not have the same issue. I

I've spent quite a bit of time trying to adjust this within the phones settings to no avail. Thank you for the help!