The modified gestures plugin version 0.0.4 is out. I fixed some bugs and added configurability. Use these preferences to change the rocker gestures behavior :
kmeleon.plugins.gestures.RL (default ID_NAV_BACK)
kmeleon.plugins.gestures.LR (default ID_NAV_FORWARD)
As usual, the plugin can be downloaded
here. Hopefully it should be stable now... until I find the next bug