Parse response from remote server HTTP Auth Agent

Hi,

The setup

1. User logs in on the logon page with their social security number.
2. The variable "session.logon.last.username" gets populated with the with the social security number
3. I use a HTTP Auth Agent to send the session.logon.last.username to get authenticated by a remote server with a Custom Post.
4. Here is my issue, I need to parse the response form the remote server and save it to a variable, because the remote server are sending back the SAMaccountname of the user.

I can see that the HTTP Auth Agent sends the variable (I use a layered virtual server for SSL)

<HTTP_REQUEST_DATA>: {"SocialSecurityNumber":"XXXXX-XXXX"}

I can see that the remote server responds with the correct info.

 <HTTP_RESPONSE_DATA>: payload is {"SAMaccountname":"xxxxxxx,"}

For the life of me I can´t figure out how to parse the response.