You're going to need change the parameter to the store template under System-->Configuration-->General-->Design. Remember to select the store you want to translate under the Current Configuration Scope dropdown.
Then you change the theme value of the Skin (Images / CSS) to the directory you put those images in. For example, I use Hellococo, so I enter hellococo_tw in the Skin (Images / CSS) parameter and then upload (copy) the images to a folder called hellococo_tw in the skin/frontend/default directory.
Hope that helps. To make things simple, just copy your entire helloglam template into a helloglam_es folder and then delete the items that are the same in both templates, like CSS files and extension packages.
Hope that helps!