Detect user's real ip address using Flash

I want you create me a script using Flash which identifies visitor's real ip address even when the user is using a web proxy. The swf file should be invisible to the visitor and it should make a call to a file named [login to view URL] using ip address as a parameter. Then I will save that ip to session and prevent visitors who are using proxy to post any content to my site. Here is an example: [login to view URL] is able to detect my ip address with help of Flash when I'm using a web proxy like websiteproxy.co.uk.