I'm assuming you mean the automatic updates? If so, (and I'm assuming it is the same with the LiveCd as it is with the installed OS) you shouldn't need to update at all.
If you haven't tried this already, when you boot to the LiveCD go ahead and go into Synaptic Package Manager, and at the top left there should be a little arrow icon (like a refresh button, the pop-up should say "refresh list" or something like that). Click that. When the resulting operation has finished you should be able to download any software you like.