Okay... bring up another window/tab or whatever, after clicking "reply to thread" or "new Reply" or whatever.
Have the other tab/window on the first page where you can just copy and paste the specifics into the reply box.
Make sure you ask for them. Say something like:
Hey I just stumbled across this and saw you were doing a giveaway, may i have----
Or something similar. Just be sincere about your request and not like "give me this. NAO." and the thread holder will get back to you when they can on it. :)