ip6tables and friends look for /usr/lib/iptables/*.so etc., instead of /lib/iptables. This can be noticed with 'strace ip6tables -L'. This is caused by the fact that some part of the code was changed to IP6T_LIB_DIR, but makefile was forgotten to be changed. There is a fix in netfilter CVS for this. Also, ip6tables-{save,restore} could be added, even if they aren't of too much use yet. There is .src.rpm with these (against 1.2.2-1) at http://www.netcore.fi/pekkas/linux/ipv6/
Reminder. The fix is from CVS, and should be quite non-controversial.
Fixed in 1.2.2-3