spoofing a IP address in cfhttp

I have a application where I hit Amazon.com several times a second. Based on their rules I can only hit them 3 times a second per IP address.  So in the past what I have done is setup a COM object running on several virtual windows 2000 servers each with their own IP address and then use a Outbound IP Translator in my firewall.

We are now moving to a 100% CF solution and I have thought I saw something that said using the <cfhttpparam> tag you could spoof the IP address but doing this and sending to "http:\\whatismyipaddress.com" keeps sending back my primary address.

Does anyone have a solution for me on this as if I want to continue down a CF solution I would need to purchase server copies of CF to load on each virtual machine or use a open source CF solution but still run on the virtual machine.  All are options but not the cheapest of options.

Below is the test code i was using:

<cfhttp url="http://whatismyipaddress.com/"
    method="post"
    >

    <cfhttpparam type="header" name="host" value="192.168.2.52">

</cfhttp>

<cfdump var="#cfhttp.filecontent#">

In the above code, I am running on 192.168.2.90 but 192.168.2.52 is setup for outbound address translation so it use a public ip that is different from my main outbound ip.  But whatismyaddress.com only reports my main address.  if i go to the .52 server and run IE to whatismyipaddress.com it reports the correct one so I know the outbound translator is working just not the spoofing in CF.

thanks for your help

Jeff