[PROBLEM] CEC (new to this..)

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Hi,

I'm very new to the Rpi. I've been reading around, tried raspbmc, openelec then xbian, and seems the late one suits me the best.
I manage to set it up, with network, and all, now I'm down to the remote.

I use a logitech 700 (WAF..), so I got myself a cheap IR receiver to use with the Rpi.
The receiver seems to be working, as with its remote, I can control xbmc. Though I can't seem to be using the harmony, for whatever reason. Configured it as Microsoft MCE 2nd Ed device, but it doesn't work.

Then I read about CEC. I'm not sure I understand all that it does, nor how it works.
I use the Rpi connected to a video projector Vivitek HD1085FD, which has CEC. In xbmc, there is a CEC item in the peripherics.

Though I don't know if it just is able to power up (like you power up a tv and the pi is powered through the CEC). I've read here and there that it seems some people managed to configure their remotes but I don't find how, and I don't find if it's possible to use the harmony to do it.

Anyone can enlighten me?

Thanks !
A.