Order VS Invoice

-- HikaShop version -- : 3.0.1
-- Joomla version -- : 2.5.28
-- PHP version -- : 5.6
-- Browser(s) name and version -- : Chrome 57

When a client buys something in the Hikashop, he or she receives 2 emails:

1) Your Order..... is created
2) Your Order... is confirmed.

I would like the client to receive an INVOICE, not just an order!
Or at least the latest mail should be an Invoice. (attached as PDF preferably)

How to I accomplish this?

Regards,

Gosling