well HTTP_POST_VARS will only help in this situation
if your PHP version is 4.1.1 or lower and you are using post in your form.
If however your version is later than that i suggest using $_POST
so like this
$HTTP_POST_VARS['feild_name']
or
$POST'feild_name']
assuming that a feild in the form is named feild_name.
Now i hope that helps a little.
Now you'll need some if's
for your value so it can be shown in the form.
Now i suggest
if(isset($_POST['feild_name'])) same with HTTP_POST_VARS just change post to that.