There's a very specific place where the updates go (for example, extracted updates don't go in SP\201x\Updates - only the single .exe updates do), and also because of many changes MS has made to slipstreaming support in recent months, it's tough to say whether a certain SP / CU will properly slipstream or not. I would recommend avoiding slipstreaming altogether for simplicity, and simply put updates (e.g. office2010-kb2687564-fullfile-x64-glb.exe) inside the \SP\2010\Updates folder (or subfolder). AutoSPInstaller will pick them up from there and apply the updates when it runs, just prior to farm creation/joining.
BTW AutoSPSourceBuilder can help with downloading updates, putting them in the right location etc.
Brian
BTW AutoSPSourceBuilder can help with downloading updates, putting them in the right location etc.
Brian