ColdFusion oAuth Consumer against PHP Pantheon site - oauth

Question

I am an oAuth newbie and struggling to implement a simple oAuth consumer in ColdFusion against a PHP site which uses the Pantheon oAuth library. The following curl script works perfectly and returns the JSON I need.
curl -X POST -i -H "Content-type: application/json" -c cookies.txt -X
POST https://example.org/service/user/login?mykeyhere -d
'{"username":"myuser","password":"mypassword"}'
My question is how do i implement this in ColdFusion, returning the responding JSON into a variable that I can parse?
Thanks for your help!
Ben
UPDATE 5/3/13
Ok, I tried to translate the cURL line and am getting closer - here's what I did:
<cfset mydata = serializejson('{"username":"myuser","password":"mypass"}')>
<cfhttp url="https://example.org/service/user/login" method="post" >
<cfhttpparam type="header" name="Content-type" value="application/json" >
<cfhttpparam type="header" name="oauth_consumer_key" value="mykey" >
<cfhttpparam type="body" value='#mydata#' >
<cfhttpparam name="cookies.txt" type="cookie" value="" >
</cfhttp>
However, I am still getting a negative response - but it seems it is because I am not passing the values that are in the "-d" clause from the cURL script correctly. Any ideas?
Thanks again!
Latest update:
Tried both of these to no avail - i also removed the cookie line:
<cfset mydata = '{"username":"myuser","password":"mypass"}'>
<cfset mydata = serializejson('{"username=myuser","password=mypass"}')>
3:20 ET
Sorry - made the correction as per your comment to below - but still no luck:
<cfset myData = serializeJSON({username="user",password="pass"})>

Answer 1

Great idea on the debugging of the cURL post - I figured it out. It was just about the headers - the data WAS being passed correctly.
Once the JSON is created, here's the CFHTTP call:
<cfhttp url="https://mydomain.org/service/user/login?oauth_consumer_key=myKeyHere" method="post" >
<cfhttpparam type="header" name="Content-type" value="application/json" >
<cfhttpparam type="header" name="Accept" value="*/*" >
<cfhttpparam type="body" value="#mydata#" >
</cfhttp>
Works great - thanks to Leigh for helping me think this through!