Eshop Order receipt

[1050]

Hi,
I'm new at Elxis eshop. I want to add an invoice link at the thank.html at the end of the order steps to let customers print their receipt in order method. How could I have this?
please help me

[webgift]

Hi,
A notification e-mail will be sent when a payment order complete successfully. At this e-mail there is a Receipt URL that client can follow in order to print his receipt.

[1050]

Yes, I know, but I want to show that link in the thanks-order.html because of some rules in my country. I try to find the order ID from  Session ID by using $eshop->getSession() , but It doesn't work.I think if I can find the order ID I can give it to viewinvoce() function and show the link.