Thought I'd just let anyone out there thinking of using Flirc with an HTPC, XBMC and a Vizio Via Apps TV that it works great. My particular model is the XVT373SV (http://www.amazon.com/VIZIO-XVT373SV-37-Inch-Internet-Application/dp/B003GDFJTU). Remote works great with Flirc right out of the box without any additional programming but I did some extra ones for some needed functions. There are only some keys you can program:
Stop, Play, Pause
No other buttons respond to Flirc though likely this can be altered or changed by someone with more experience that I
I am using it thus:
Rewind: Windows Key. With Windows 8, this allows the Metro screen to pop back up, which allows me to use the up/down/left/right to navigate Metro
Fast Forward: Launch XBMC with a programmed Windows shortcut key: Ctrl-Alt-M
Stop/Play/Pause: Works immediately with no programming with WMP, XBMC, and VLC
Up/Down: In addition to navigation in XBMC and Windows without having to program it, when playing a movie, Up/Down will move between chapters. If there are no chapters, 10 minute intervals.
Left/Right: In addition to navigation in XBMC and Windows without having to program it, when playing a movie, Left/Right will go back/forward in 30 second intervals in XBMC.
Menu: Exit XBMC (if on XBMC home screen). When navigating folders/files, it will jump to the bottom for quick access to moving between directories.
Last: Jump to home screen in XBMC.
Thinking of testing the key repeat function in the beta firmware. Tried to load the FW for wake from sleep but it failed the upload and the Flirc app crashed. Had to re-load FW 1.0 to get it working again.
Another odd quirk. If you program the remote to respond on a particular input on your Vizio TV with XBMC, such as HDMI-1, it will not work on any other port. Let's say you move your XBMC to HDMI-2: the remote no longer responds or sends the proper commands. Tried wiping the config on Flirc and re-loading FW but no dice. My guess is that something on the remote has to be reset before it'll push to that other input for XBMC but I just moved it back to the other port as my goal was to make it easy. I can attach my config if anyone needs it or wants it. Otherwise, just here for info for other potential XBMC users who are trying to decide if the Vizio line of TVs is going to work for them. I can state that I am able to access everything I need with one remote with ease.
I use a tiny touchpad/QWERTY keyboard for navigating and using other Windows functions such as Firefox or Handbrake but for movies and such via XBMC, the default remote from Vizio, works flawlessly with Flirc.