I've done exactly what you explained. In my "JSONRequest", my property starts with an upper case letter: "Step", but in my json request it is "step" with a lower case letter. Is it possible to map "step" into "Step"? Or I should create my property with a lower case start letter?
Is there any particular reason you want to map "step" --> "Step"?
You can use lowcase "step" in your application without any problems.
Anyway, if you really want to have "Step", then use a data layer on top of your integration. For example, you could create a data page wher in a response data transform you would set "Step" value (Data class) from "step" (Integration class)
Basically, that's true. Whenever possible, we must use camel case.
But it's a bit different for an integration - here's a convension is an interface specification. But later you could translate it to your application layer through data layer (as I described above) and use camel case again