I eventually located the configuration file, and you'd have to give up CEC (if you switch between HDMI and composite video) to make it compatible. And here is how:
- Start up OpenELEC
- Connect from a remote computer via ssh to openelec as user root (default password is openelec)
- Edit (with vi) the file /storage/.xbmc/userdata/peripheral_data/rpi_2708_1001.xml
- Find the line
, and change the value to "0"