This is the same for preset codes in DISH, Cable, Directv and addition to tivo remotes they all are missing the input command for vizio.
Certain UEI made cable remotes can use advanced codes to enter the popular input command. The newest directv white remote the rc64 now has code with right input command, code in it is tv 11758.
Non-learning tivo remote owners are out of luck, sorry. If you were to get GLO tivo remote, you could teach the input command from the vizio remote.
The cable remote owner above, the advanced code for input using setupcode 0178, is advanced code 090 or 00090.