iptables RPC module

I'm trying to limit Sun RPC connections to things that managed to get
to the portmapper first. In older iptables I've found the -m record_rpc
option and in newer iptables I can try things like,
iptables -A INPUT -m rpc --rpcs <whatever ...> -j ACCEPT
but I can't get it to work: it just says,
iptables: No chain/target/match by that name

I tried compiling the kernel with things like CONFIG_IP_NF_CONNTRACK
and CONFIG_IP_NF_MATCH_CONNTRACK but they don't seem to help. iptables
otherwise seems to be working fine for me.

Am I going about this wrongly? Help would be appreciated.

-- Mark