Hi Pavol,
I'm not sure what may have happened. I do know that some JSF impls are incompatible with some Richfaces versions.
I'm happy to report that Multi-JSF is now fully integrated into master. So you can build the very latest from here or you can wait until tomorrow and download the latest nightly build from here.
Yes, it is ready for deploying apps. If you stil have a problem, please report bugs here.
Stan