Slow fix:
write this function, and convert order array into a cart, order data are here, but the mail content generation uses cart

function prepareMailData(){
if(empty($this->vendor)) $this->prepareVendor();
//TODO add orders, for the orderId
//TODO add registering userdata
// In general we need for every mail the shopperdata (with group), the vendor data, shopperemail, shopperusername, and so on
}
Gyuri