XML-RPC HTTP request with App Inventor?

Question

I am trying to build out an app that will communicate with Tapatalks API, it uses XML-RPC HTTP requests, I can do post/get requests with the web component. I cannot find anything on modifying the web component/Blocks to create said XML-RPC encoding. Any resources? Tips of what to search, or insight would be appreciated.

This is the API php code I am trying to interact with https://github.com/tapatalk/tapatalk-phpbb3/blob/master/root/mobiquo/function/login.php

Here is my app blocks currently and I am getting a code 200

Here is my blocks editor : http://imgur.com/uEyOb8i

Answer 1

What you tried looks very strange, but at least you tried something ;-) ... You somehow mixed a POST and GET request, there is no header defined and where is the xml format?

Probably it helps to read this first: What is a XML-RPC Request

Then concerning App Inventor you can try to use the following blocks.
EDIT: update of the screenshot to make things clearer.