Yes i've got the exact same problem. I'm running Ableton Live 8/Logic Pro 9 on OS X Lion.
It seems that the RMX has not been mapped to the plug-in. It will allow me to map other parameters outside of the the plugin to the hardware, but I cannot use the controller to effect the plugin.
I've exhausted all options, installed all the latest versions, gone back to old versions to see if that worked and updated the firmware etc.
Any ideas of what's going on here please?