Unfortunately most of the conntrack/nat helpers in patch-o-matic were broken ever since 2.6.11 was released. The reason is the new semantics of the redesigned conntrack/nat helper API by Rusty Russell and Pablo Neira.
It's not an easy and straight-forward port, and as usual there were not many people volunteering for that job. Max Kellermann is a positive example, he ported the h323 helpers.
I've now ported the all remaining ones BUT the PPTP helper. At the moment I'm not sure whether the PPTP/GRE helper can be ported/used at all with the new infrastructure :( This will need some serious amount of thinking.
All the ported helpers are available from pom-ng. I don't have the possibility to test them, since I don't actually use most of those protocols. Testing / debugging / bug reporting is therefore very welcome. Anyone writing a test case for nfsim would be my personal hero.