Infusionsoft Campaign Builder - How to Create a New User from HTTP Post?

I'm trying to create a new user from an HTTP Post from the Campaign Builder with Infusionsoft but for some reason it's not working. It works fine when an order is placed from the billing automation.

Here's how I have i setup:
http://screencast.com/t/CMWBD7mSc49

Any idea on what values to pass over?

Is this correct?

Have you made any progress with this? I am trying to do something similar and need some assistance.

I'm also very interested in this...