Urban Outfitters Student Discount

Hello, does anybody know how to redeem a student discount online at Urban Outfitters.
They do definitely do a student discount but I cant seem to manage to get it working on the internet, I have tried typing in the number on my NUS Extra card which is the way Asos do it and I have looked on the NUS website but there is nothing there...
Really want to buy my boyfriend a shirt so if anyone could help that would be great.
Thank you

What I did was I bought it online, then went to the store and told them that I want to return them and buy them back and use a student discount - genius!