This provides a very basic interface to http; it should be considered poorly built, lame, and dangerous until further notice. That said, if you GET or POST form data name/value pairs to the proxy port using HTTP, the proxy will treat it as Name: Value input and will act on it, and will respond back in whatever format you want to use. A useful scenario might be to use http input and xml output. The following form can be used as a test:
Action:
ActionID:

See samples/httpast.html for a sample file that implements this. It would be best to use this with autofilter=on since right now you are only going to get one response block back, and it might as well be relevant. :)