The text box now shows up. However, I have a different problem - the discount is not being applied. I've gone through the steps of creating a discount code, given it a name, specified the number of items, flat rate amount etc. -- but when I try to input the code and test it out, it still shows up with the original price on the PayPal site.
I'm putting the full price of the book in the "discount" field, since I want those who have the code to be able to download it for free. But it's still showing the original amount?
What am I doing wrong?? - Is there a lag in the system?