How do I activate my external HD on my PS3?

I followed all the steps here http://www.ehow.com/how_2222076_add-external-hard-drive-playstation.htmland when I browse around my PS3 it shows up(Like the music/video sections and the memory card utility and both of thesaved data utilitys are both showing the external hard drive as being there) but when I try to download something it still says I dont have enough space.. and the external HD has 300GB of free space on it. Is there something else I have to do like activate it on my PS3 ?

what are you trying to DL to it?

Little big planet demo, I used up most of my space with the DC Universe betaryuz4ke1

[QUOTE="ryuz4ke1"]Little big planet demo, I used up most of my space with the DC Universe betajt4mtb