Tivo updated their systems I believe its for cetain cable box that this works:

Within the Tivo's multitude of menus under Remote Set Up I found ZVOX listed with codes: 2026,  2065, 2027. I followed their instructions regarding TIVO remote: 

#1. "Hold down the TV POWER and Tivo buttons together for 5 seconds---until light at top center of remote remains on. 

#2. Enter 4 digit code (I used 2026).

#3.  Test the TV POWER button."  This worked and I can now control Vol. Mute and Power for the ZVOX from my Tivo remote.