Why do you think you need to decide which tuner to use? The box does it automatically. You cannot tell it which tuner to use, the logic it applies is to use the tuner that ties up fewest resources first. The default is for recordings is to take priority over viewing. So if the transponders you are accessing for recordings max out your tuners, you will only be able to view/record the transponders that are in use. Please forget about selecting tuners, the box does it automatically. You just pick the channels.
I don't have the remote. Isn't there a media or list button? Press that and it will show you the recordings.