so, I am making slow progress on building a service that handles the operations, url parms, and JSON bodies.
if I do NOT use the JSON DPH, then the parm matching is what is exactly coded in the VSI transaction.
but I cannot easily access and use data elements in the JSON input body.
if I DO add the JSON DPH, then the json body is converted to properties, AND arguments
but because the JSON document is variable size, it will only match one of 1000s of choices..
and will NOT match ANY META selection. (except the one where the exact set of parameters match for the meta transaction