Situation A:
When selecting a program to watch I press the center button (Play) and then press the Help button to switch into the Play mode. Then the keys operate the same as on the Tivo for fast forward, rewind, pause etc.

Situation B:
I press the "ZAP" button to get back into the Tivo menu mode and then navigate to delete. However, that is personal preference. Another option would be to remap the STOP button (which is meaningless in PLAY) to send the left IR and switch into naviage mode. This would let you send the down down enter sequence, which puts you back into Tivo menu with navigate keys