I have 10 feedburner feeds that are for different categories on a wordpress site.

I would like to modify the subscribe form code feedburner supplies to include radio buttons to select which of the feeds to subscribe to.

Code:
<HTML>   
<HEAD>   
<TITLE> Radio Window </TITLE>   
<script>   
  function OpenWindow(){   
    for(i=0;i<document.FormName["RB1"].length;i++){   
      if(document.FormName["RB1"][i].checked){   
    window.open(document.FormName["RB1"][i].value);   
    break;   
  }   
}   
  }   
</script>   
</HEAD>   
<BODY>   
<form name="FormName" style="border:1px solid #ccc;padding:3px;text-align:center;" action="http://feedburner.google.com/fb/a/mailverify" method="post" target="popupwindow" onsubmit="OpenWindow()";return true">
<p>Enter your email address:</p><p><input type="text" style="width:140px" name="email"/></p>
<input type="radio" name="RB1" value="http://feedburner.google.com/fb/a/mailverify?uri=feed1&amp;loc=en_US">Option 1<BR>
<input type="radio" name="RB1" value="http://feedburner.google.com/fb/a/mailverify?uri=feed2&amp;loc=en_US">Option 2<BR>   
<input type="radio" name="RB1" value="http://feedburner.google.com/fb/a/mailverify?uri=feed3&amp;loc=en_US">Option 3<BR>
<input type="radio" name="RB1" value="http://feedburner.google.com/fb/a/mailverify?uri=feed4&amp;loc=en_US">Option 4<BR>   
<input type="radio" name="RB1" value="http://feedburner.google.com/fb/a/mailverify?uri=feed5&amp;loc=en_US">Option 5<BR>
<input type="radio" name="RB1" value="http://feedburner.google.com/fb/a/mailverify?uri=feed6&amp;loc=en_US">Option 6<BR>   
<input type="radio" name="RB1" value="http://feedburner.google.com/fb/a/mailverify?uri=feed7&amp;loc=en_US">Option 7<BR>
<input type="radio" name="RB1" value="http://feedburner.google.com/fb/a/mailverify?uri=feed8&amp;loc=en_US">Option 8<BR>   
<input type="radio" name="RB1" value="http://feedburner.google.com/fb/a/mailverify?uri=feed9&amp;loc=en_US">Option 9<BR>
<input type="radio" name="RB1" value="http://feedburner.google.com/fb/a/mailverify?uri=feed10&amp;loc=en_US">Option 10<BR>   
<input type="submit" value="Subscribe">   
  </form>   
</BODY>   
</HTML>
This is the code I have put together searching the web, when hitting the subscribe button after entering a email address and selecting an option it load two new windows, one for the relevant feed but does not transfer the email address entered in the text box.

The second for to http://feedburner.google.com/fb/a/mailverify

All help would be greatly received.