MX Component radiobutton - value in PHP?

Hi,
I´ve set up a FlashMX movie, containing a form with the MX Component "radiobutton" for letting the user make a choice between 3 options. There are several other fields in this form. I send them to a PHP-page, validating the entries.
Everthing works exept getting the variable/value of the f... radiobutton. Has anyone an idea how to asign those in PHP?

Here´s the code:

<?php
echo $name;
echo $email;
echo $message;
echo "you have $radio_option selected";
?>

"radio_option" is the Parameterentry in "Data" in Flash.

What´s wrong about it?
Thanks, nixdesigner :confused: