I hope code is good. Does check for ST and not existant shows BT box instead. Please advise if good code. I tested and works.
<div class="output-shipto">
<!-- adding code to change ship to to bill to and back -->
<?php if (empty($this->cart->STaddress)){
foreach($this->cart->BTaddress['fields'] as $item){
if(!empty($item['value'])){
if($item['name']==='agreed'){
$item['value'] = ($item['value']===0) ? JText::_('COM_VIRTUEMART_USER_FORM_BILLTO_TOS_NO'):JText::_('COM_VIRTUEMART_USER_FORM_BILLTO_TOS_YES');
}
?><!-- span class="titles"><?php echo $item['title'] ?></span -->
<span class="values vm2<?php echo '-'.$item['name'] ?>" ><?php echo $this->escape($item['value']) ?></span>
<?php if ($item['name'] != 'title' and $item['name'] != 'first_name' and $item['name'] != 'middle_name' and $item['name'] != 'zip') { ?>
<br class="clear" />
<?php
}
}
}
} else {
if(!class_exists('VmHtml'))require(JPATH_VM_ADMINISTRATOR.DS.'helpers'.DS.'html.php');
echo JText::_('COM_VIRTUEMART_USER_FORM_ST_SAME_AS_BT');
echo VmHtml::checkbox('STsameAsBT',$this->cart->STsameAsBT).'<br />';
foreach($this->cart->STaddress['fields'] as $item){
if(!empty($item['value'])){ ?>
<!-- <span class="titles"><?php echo $item['title'] ?></span> -->
<?php
if ($item['name'] == 'first_name' || $item['name'] == 'middle_name' || $item['name'] == 'zip') { ?>
<span class="values<?php echo '-'.$item['name'] ?>" ><?php echo $this->escape($item['value']) ?></span>
<?php } else { ?>
<span class="values" ><?php echo $this->escape($item['value']) ?></span>
<br class="clear" />
<?php
}
}
}
}
?>
<!-- Ending my code here -->Original code
<?php
if(empty($this->cart->STaddress['fields'])){
echo JText::sprintf('COM_VIRTUEMART_USER_FORM_EDIT_BILLTO_EXPLAIN',JText::_('COM_VIRTUEMART_USER_FORM_ADD_SHIPTO_LBL') );
} else {
if(!class_exists('VmHtml'))require(JPATH_VM_ADMINISTRATOR.DS.'helpers'.DS.'html.php');
echo JText::_('COM_VIRTUEMART_USER_FORM_ST_SAME_AS_BT');
echo VmHtml::checkbox('STsameAsBT',$this->cart->STsameAsBT).'<br />';
foreach($this->cart->STaddress['fields'] as $item){
if(!empty($item['value'])){ ?>
<!-- <span class="titles"><?php echo $item['title'] ?></span> -->
<?php
if ($item['name'] == 'first_name' || $item['name'] == 'middle_name' || $item['name'] == 'zip') { ?>
<span class="values<?php echo '-'.$item['name'] ?>" ><?php echo $this->escape($item['value']) ?></span>
<?php } else { ?>
<span class="values" ><?php echo $this->escape($item['value']) ?></span>
<br class="clear" />
<?php
}
}
}
}
?> 
