if you want to remove the continue button on the step file, you can change the line:
if($this->continueShopping){
to:
if(false){
If you want to add the continue button on the cart file, you can add the code below at the end:
<?php
if($this->continueShopping){
if(strpos($this->continueShopping,'Itemid')===false){
if(strpos($this->continueShopping,'index.php?')!==false){
$this->continueShopping.=$url_itemid;
}
}
if(!preg_match('#^https?://#',$this->continueShopping)) $this->continueShopping = JURI::base().ltrim($this->continueShopping,'/');
echo $this->cart->displayButton(JText::_('CONTINUE_SHOPPING'),'continue_shopping',$this->params,JRoute::_($this->continueShopping),'window.location=\''.JRoute::_($this->continueShopping).'\';return false;','id="hikashop_checkout_shopping_button"');
}
?>