The HTTP receivers don't appear in the input configuration. They're just REST endpoints that any logged in REST session can send data to. They are also the least performant of Splunk's inputs, and you should avoid them if you have other options. You will be much better served by writing to a file and monitoring it with a universal forwarder, or writing directly to a TCP or UDP input.
Your best bet is to email Damien Dallimore, who wrote the code, directly.
