Hi,
I think that you are talking about the "Register" button in the checkout for adding an address, the translation line is "HIKA_REGISTER".
The continue shopping button is present in the view "chekout / step" to display it to the top, you have to place the code upper in the same file. The code is:
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"');
}