GO TO :
DVR in your FiOS Mobile app.
In upper Right make sure that next to picture of Remote it indicates the name of the Set Top Box connected to that particular TV you want to control.
Make sure your TV and Set Top Box are ON
Touch the picture of the Remote
If some of the Remote picture does not show what you want to do with the Remote
move it.
USE(touch) THE REMOTE CONTROL PICTURE TO DO WHAT YOU WANT.
Just did it and it works for me. Using iPad2 with FiOS Mobile Version 5.3
If you are the original poster (OP) and your issue is solved, please remember to let all of us know and click the "Accept as Solution" button so that others can more easily find it. If anyone has been helpful to you, please show your appreciation by clicking the "Kudos" button.