Radio button info on checkout page not retained after clicking modify on confirm page

I added a radio button choice for prefix. It is posted to the confirm page, but when I go back of hit modify, the value is not retained.

This is what I tried:

<label>
<input type="radio" name="prefix" value="<?php echo $row_rscontent8['description23']; ?>" id="prefix" <?php if(isset($_POST['prefix']) && ($_POST['prefix'] == '<?php echo $row_rscontent8[\'description23\']; ?>')) echo "checked";?> />
<?php echo $row_rscontent8['description23']; ?></label>&nbsp;&nbsp;&nbsp;
<label>
<input type="radio" name="prefix" value="<?php echo $row_rscontent8['description24']; ?>" id="prefix" <?php if(isset($_POST['prefix']) && ($_POST['prefix'] == '<?php echo $row_rscontent8[\'description24\']; ?>')) echo "checked";?> />
<?php echo $row_rscontent8['description24']; ?></label>

It is not working though.

I also tried the code below, but still no luck. All values on the checkout page are retained, except for the radio buttons.

<label>
<input type="radio" name="prefix" value="<?php echo $row_rscontent8['description23']; ?>" id="prefix" <?php if (!(strcmp($row_rscontent8['description23'], (isset($_GET['valid'])?ValidatedField("confirm_046","prefix"):(isset($_SESSION['eCartCheckoutForm_prefix'])?$_SESSION['eCartCheckoutForm_prefix']:""))))) {echo "selected=\"selected\"";} ?> />
<?php echo $row_rscontent8['description23']; ?></label>&nbsp;&nbsp;&nbsp;
<label>
<input type="radio" name="prefix" value="<?php echo $row_rscontent8['description24']; ?>" id="prefix" <?php if (!(strcmp($row_rscontent8['description24'], (isset($_GET['valid'])?ValidatedField("confirm_046","prefix"):(isset($_SESSION['eCartCheckoutForm_prefix'])?$_SESSION['eCartCheckoutForm_prefix']:""))))) {echo "selected=\"selected\"";} ?> />
<?php echo $row_rscontent8['description24']; ?></label>

radio buttons use "checked" instead of "selected"... try changing that in the code.

Thank you, Ray. After a day of trial and error, trying a ton of code snippets of the internet, I actually came so close.. Thanks again :)