OK - I think I get it now. Sometimes takes me a while.
You can't run 'Digium FAX' or 'SpanDSP FAX' on Digium supplied Asterisk RPMs (such as we use in SARK). The FAX modules aren't included in the RPM. They are anyway, mutually exclusive so you have to pick one (Digium or spandsp) and recompile Asterisk to include it. So, you would need to build your own Asterisk, which is fine but it's not really an option for us for SARK/SAIL unless we change the way our iso works.
In answer to your question "can you generate an IAXmodem template like the one in the wiki?", the answer is yes but I'm not sure if we would want to. The original code only retrieved 4 variables from the database so its a bit overkill to put it into a database and to write all of the surrounding CRUD code to look after it. I think I'd be tempted to take it out of SME templates altogether and just update the base file. It's not like it's going to change very often.
Best
Jeff