I've never done that, but if you add it as a menu item, can you then go to View -> Toolbars -> Customize and find it in the commands tab? And if so, can you drag it to the toolbar you want it on from there?

Depending on your needs, you might consider creating a class that extends both %Net.HttpRequest and %JSON.Adaptor and using the %JSON.Adaptor methods to create a JSON representation of the instance. That would be easier to analyze.

Your result.HttpResponse.Data can be either a string or a stream object. If it's a stream object you'll have to handle it a little bit differently using result.HttpResponse.Data.Read():

set response=result.HttpResponse.Data.Read()
while 'result.HttpResponse.Data.AtEnd{
    set response = response_result.HttpResponse.Data.Read()
}