In order to use the external rpc patch you basically need to perform the following steps:

• Download the patch-o-matic suite:

  svn co https://svn.netfilter.org/netfilter/trunk/patch-o-matic-ng \
  patch-o-matic-ng.download

• Check the sources.list file:

  The sources.list file must contain a specification for the external rpc patch. See sources.list.

• Run the patch script:

  KERNEL_DIR=Your_Path_to_KernelSources \
  IPTABLES_DIR=Your_Path_to_IptablesSources \
  ./runme --download --batch pending