I recorded a macro for the Power button and learned both the power command for my TV remote and the power command for my FIOS remote.
And about 30 seconds later I realized that my FIOS remote turns both devices on when I press "Power", because when I tested the learning on the IR34A, my TV turned on, the FIOS box turned on and the TV turned off again. Duh.
Then I re-recorded the learned command for the power button just from the FIOS remote, which was already programmed to send both codes.
Then I reset the FIOS remote to only turn on the FIOS receiver and assigned that to a side button, in the event I want to switch from the FIOS box to another device, need to keep the TV on but want to turn the FIOS box off.
See pages 25-35 in your manual for instructions.
Good luck!