Ive just done the exact same thing.... i wish i had read this post before hand lol. all the lcd replacements ive found online already come with the black lens attached so im no doubt going to have the same problem with them aswell....
its just occured to me... i replaced my screen on my ipod touch not so long ago and I had to steam the screen away from the lens to replace it..... so im guessing its the exact same thing with this.... wish I'd remembered that lol