Can't supply param for jump

We need to change the maximum segment size, which we do via the iptables command "-A FORWARD -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu"

Although this module allows us to set "jump => 'TCPMSS'," there is no way to add the necessary '--clamp-mss-to-pmtu' param afterwards: the 'jump' param doesn't allow the param, and there is no 'jump_args' type param to supply it separately.